1.

The invention of money

The Roman army on manoeuvres: first century CE, on the North Sea coast, roughly where Belgium now stops and the Netherlands starts. Plinius Secundus was one of the commanders, and when he came to write his famous natural histories, he remembered what he had seen.

There were wide salt marshes and he saw no trees at all. He could not make up his mind if he was on the land or on the sea. There were houses built on hillocks and he thought they looked like ships in the water, or maybe more like shipwrecks; he reckoned the houses must be built that way to escape the worst daily surges of the tides. He sounds almost nervous in this strange marsh landscape, being an inland Roman and used to having the ground stay firm under his boots; now he was looking out at a landscape of shifting clay, all cut up with creeks and gullies where the tides pushed salt water in and out. He might as well have left the empire altogether because this coast was cut off from the mainland by lagoons and brackish peat, as good a frontier as the forests that kept whole peoples apart, better than any river. To reach the marshes, and the water people who lived there, you had to know the marshes. You also had to be welcome, because you would be seen.

Pliny considered the water people and he decided they were not worth the bother of conquering. Fish, he wrote, was all they had.¹

Seven centuries later opinions had not much changed. Radbodo, Bishop of Utrecht, was most uncharitable about the Frisians, the people of these marshes: he wrote that they lived in water like fish and they rarely went anywhere except by boat. They were also crude, barbarous and remote: sodden provincials.² And yet between the writing of those two accounts the Frisians reinvented all the links and ties across the North Sea, as far as Jutland at the northern tip of Denmark and even beyond. They founded a new kind of town on the coast that thrived as the old Roman towns were in decline. They made themselves a capital on the left bank of the Rhine at Dorestad, just where the river divides to run down to its delta, which became the turntable of all Northern trade. And they ruled the North Sea, dominating all the trade that went by water, so for a time its name was changed: the Frisian Sea.

They did something else which helped to shape our world: they reinvented money. They took coins with them on their trading voyages, money for buying and selling and doing business. Other territories had run out of cash, or lived off gifts and barter, or stopped using money for anything except tax and politics, but the Frisians carried the idea of using money wherever they went. It was not at all a trivial idea. With it came ideas of the value of things and how to calculate that abstract value on paper – the value that objects in the real world share, a pot with a pile of grain with a fish with a plank with a place in a boat going up the Rhine, even when it seems obvious they have nothing else in common at all. The idea of value had to work wherever the Frisians came ashore. Trading meant taking that value and working with it, even experimenting with it: seeing the world in mathematical terms.

Money was going to change people’s minds.

That story is easy to miss, but then it is extraordinary how much Pliny missed and he was there. He saw ramshackle shipwrecks on the little hills, most likely fishermen’s shacks, and missed the solid houses with their sod walls a full metre thick. He didn’t notice the real business of the marshes.

He says nothing about the two temples facing each other across the water at the start of the open sea, on the very last point of the land: Roman temples dedicated to Nehalennia, a goddess of death and trade and fertility, almost everything that matters. On her altars, salt merchants gave thanks for voyages she had made successful, and so did men who dealt in potter’s clay and fish sauce, wine, cloth and pottery and anything that was going out to England across the sea; sometimes the same merchant thanked her on both sides of the river.³ At the temple in Colijnsplaat, to the north, the goddess was all business; the one to the south, at Domburg, where the stones later came back from under the sea, makes clear her darker side. Here she has a hound sitting by her, as she stands by a set of curtains that screen away a passage to the next world; she is watching over the dead as they go out to sea, sailing west to the isles of the blessed.⁴ Practical cargoes and magical journeys, life and death, were all going over the beach at Domburg.

A hundred years later there would have been nothing much for Pliny to miss. Domburg was abandoned. Pirates moved in, some of them local and Frisian, some of them from the Frankish kingdoms to the south.⁵ Rome began to lose control. Then the water took over by force: the sea rushed in and drowned the temples around the end of the second century. The dunes moved, the channels for boats changed, and the site became impossible. All that was left was a fragile stretch of sand which a single wind storm could skirl into a new landscape, a coastline where a surging sea could wash away all the business that had made so many merchants give thanks to the goddess. There was no sign of life or business there for almost four centuries until the story began over again.

But in the marshes there were heavy barges which had come down the Rhine from the middle of Europe, boats thirty metres long and three metres across, steering oars forward and steering oars aft: solid, flat-bottomed craft made out of thick slabs of oak. They were rowed and hauled down the river, carrying loads of slate and stone, or wine or pots, and when they reached the marshes, they moved their cargo onto sea-going ships.⁶ From the marshes, the goods could go north or south by sea in the lee of the islands along the coast, down to where Calais now stands to cross to England or directly across the sea to markets where York and London and even Southampton stand now, or up to the start of the Danish peninsula, where they could cross by land and river into the Baltic and reach up to Birka and Helgö in Sweden. The marshes held the trade of half a continent.

All this is unfamiliar in part because there is so little written evidence. We wouldn’t know that ‘Frisian’ meant ‘merchant’ in seventh-century London, except that Bede mentions in his History that some young aristo from Northumberland ended up in Mercian hands, and was sold in the market to ‘a Frisian’. This Frisian couldn’t manage to keep the kid safely tied up, and so allowed him to go off and ransom himself.⁷ Bede says he checked the story with particular care, so we can assume that Frisians were practical merchants who did not deal in bothersome merchandise. We would find it hard to prove that there was a Frisian colony in eighth-century York, except that Altfrid wrote the life of a saint called Liudger and mentions the time a Frisian merchant happened to brawl with the young son of a local duke and the boy ended up dead; at which point all the Frisians, Liudger included, got out quickly for fear of the anger of the young man’s family. Frisians stuck together, like any expatriate community.⁸ We owe the idea that Frisians had a distinctive kind of ship, nothing like the Viking ships, to the Anglo-Saxon Chronicle, which mentions in the entry for 896 that King Alfred ordered fast, steady longships to be built with more oarsmen than ever before, and ‘they were neither of Frisian design nor of Danish’.⁹

The abbey at Saint-Denis, close to Paris, has a royal document which guarantees that its monks will keep all the revenue from selling wine at their annual fair and also extract a kind of commission from the merchants ‘Saxon or Frisian or people of other indeterminate nations’.¹⁰ So the Frisians were important in the wine trade. It is likely that the Bishop of Liège in modern Belgium had to send to Domburg for his German and his Alsatian wine.

The stories of saints, meanwhile, bear traces of how the Frisians worked up and down the Rhine. St Goar was a hermit left in a cell by the Rhine not far from the alarming Lorelei rocks, where the river was twenty-seven metres deep and the surface was a roil of violent currents; passing travellers might well be in need of miracles. One Frisian merchant was carried downstream onto the rocks, asked the saint for help and was saved; he had on board a garment of silk splendid enough to be his offering of thanks, so he must have been a middleman shipping exotic and valuable goods since Frisia produced wool, not silk. Another was being hauled upriver by porters, alone in his boat with one servant, and refused to stop to pray to St Goar. He couldn’t steer on his own, the current dragged him over to the dangerous side, all the porters managed to drop the rope except for one. The boat smashed on the opposite shore, and the body of the last porter was found, drowned, at the end of the rope. The merchant now thought that a prayer might be in order. The drowned man revived, stood up, coughed some blood and went back to leading the porters who were hauling the barge. The grateful merchant left a full pound weight of silver to thank the saint, which must mean he was carrying much more than a full pound weight of silver coins; business was good.¹¹

This sparse patchwork of clues can now be combined with the physical record, the evidence that has been dug out of the earth or washed up on the beaches. Together they tell a story that was almost lost, as the story of losers tends to be. The old Frisians were enthusiastic pagans, so when they stopped smashing the skulls of passing saints and accepted Christianity, they were not supposed to honour their pagan past. They were subjects inside the Frankish empire that Charlemagne was building, whose pride in their separate identity and their past had been known to send them on murderous raids up the Rhine against the imperial powers; defeated, they were supposed to adopt the empire’s history. Worse, they did not have a land fit for monuments. They lived in a water world where high tides and sandstorms could cover or ruin their past: ‘a pagan people divided by the intervening waters into many farming hamlets, with all kinds of names but belonging to just one people’.¹² Even in the years when they owned the sea lanes, the sea could ruin them. The water swept back over the land at full moon in 834, flooding the land strongly; and again in 838 when the earth shook, the sun burned the earth, there were dragons in the air and around Christmas high winds broke the usual pattern of the tides and whipped the sea inland, wrecking houses along the coast and levelling the high dunes; more people died than it was possible to count, although there were curiously precise reports that 2,437 people died.¹³ Being out at sea, with all kinds of choices to make, was sometimes more secure than staying on land with none at all. Again in February 868, when a comet passed overhead, the winds got up and a vast flood killed many who were not prepared for it. That year, the famine was so terrible that men ate human flesh to survive.¹⁴

Yet the Frisians lived well on these difficult margins. They had a long record of being separate, and being independent.

They left their first traces on the east shores of the Aelmere, a sealed freshwater lake that was later flooded from the sea and became, for a time, the salt Zuiderzee and is now the freshwater IJsselmeer. They moved as the other peoples of Northern Europe began to move: some pushed, some ambitious, some displaced. They went east up to the River Weser, and west to the delta of the Rhine, the Meuse and the Scheldt. As political boundaries shifted, as the Franks wanted a name for their neighbours, Frisia grew. The islands and marshes of Zeeland, where the temple at Domburg once stood, became the nearer part of Frisia.

As they were settling, the Germanic peoples across the Rhine, famous for their seamanship, were also on the move. Many shipped out to England: Angles, Saxons, Jutes. Some went overland into Gaul. Some of them chose to stay in the new Frisian territory, which made them Frisian; before there were passports and papers and notions of national identity, or even national history, you identified with where you happened to be, not where your mother and father were born. Your identity was lived in the present tense.

Since these Frisians spoke a language much like Saxon they never had to lose touch with their countrymen and cousins now in England. So these water people had connections in place over land and over the sea: south to Gaul, east to Saxony, as well as north and west to Jutland and to England.

It took one other tidal move of human beings to give the Frisians their living. Tribes who poured into Eastern Europe in the sixth century blocked the old trading links between Scandinavia and Byzantium, the river routes that tracked across what is now Russia. Any goods that Scandinavians wanted had to come by some other route and from some other source, and so they came up from Frisia; in the two centuries before the Viking times began around 800 CE, everything that we know reached Scandinavia came by way of Frisian traders.¹⁵ They had a monopoly without the need to create it.

Along the coast the Frisians made slipways so they could build their flat-bottomed boats, the kind that moved easily in the shallow waters between the dunes and the coast. These boats could be beached on any stretch of sand and their bows and stern came up sharply so the incoming tide could get underneath to float them. Since the easiest trade routes were over water, the beaches were the obvious places for markets. The markets led to year-round settlements, and those settlements became quick, small and independent towns: ‘mushroom’ towns.

Inland towns depended on royal favour, or a local lord who required taxes, or on the presence of a church or a monastery; these economies were about supporting their masters. Monasteries were factories and farms and workshops, turning out all kinds of goods: shoes for holy feet, saddles for holy riders, swords and shields when needed, leather and cloth and gold. They had builders, blacksmiths, glass-makers; but all this was so the monastery itself could be self-sufficient. They did not make to sell or trade; and when they took goods from the towns around them, they took them as tribute, not as business.¹⁶

On the coast, individuals did business for themselves. Frisians opened up the trade routes that had been dormant since Rome fell, and added some: they sold pots, wine, human slaves. They shipped and sold whatever people wanted. The name of Frisian came to mean merchant, overseas trader, the perfect example of the long-distance seaman. The sea was truly ‘the Frisian sea’.

The water people chose their place in the world. It had once been possible to build directly on the surface of their salt marshes, but that was five hundred years before Pliny passed by. When the sea rose again and broke into the land, human beings were faced with a choice. The obvious tactic was to run away, which is what happened almost everywhere else; water people could move like so many other peoples who were moving across the face of Europe. Instead, the Frisians chose to stay and keep their place on the edge of things.

For that, they had to build their own land. They heaped up hillocks on the marshes, built on them, and the hillocks became permanent settlements all the year round: the terpen. They owned the land outright as peasants never could in the feudal systems around them, and they were settled and at home; you can tell because houses were rebuilt again and again, twice or more in a century, but always on exactly the same site.¹⁷ They also had to co-operate, house to house, terp to terp, if only because finding sweet water was never easy, not even when wells replaced the old clay-lined reservoirs for collecting rainwater; the supply of water to drink depended on the discipline of the community.¹⁸ Co-operation, not always within the law, was a Frisian habit.

As the farms on terpen disposed of their rubbish, the terpen grew taller. Each hillock started as a single farm, but as they expanded they merged one into another to form villages on higher ground: communities of houses built round an open space at the top of the terp, the back doors for the cattle and sheep to wander out onto the salt pastures, the front doors facing each other across the common space.

Anyone who lived there had to be a boatman, or they were trapped; they were peasants raising beasts because the salt land would not support most grains. Their situation gave them the advantage over inland farmers who ploughed and sowed and tended and reaped and were generally busy all year round. As cattlemen and sheep herders they weren’t tied to the land day by day, always working to make the next crop happen. Ram and ewe, bull and cow, would do that for them. They were left with the luxury of time.

Their kind of farming had other advantages. The rest of Europe around them lived on cereals, on bread and beer and gruel, and a pot kept permanently bubbling on the fire with anything sweet or savoury or fleshy that would help the gruel down. A poor harvest meant starvation, and crop yields were low at the best of times, just enough to keep people alive. The Frisians were rich by comparison. They had grazing for their animals, mostly cattle; so they had milk and meat as well as fish and game, a diet that was nourishing twelve months a year. For a while, the marshes that Pliny dismissed were more densely populated than anywhere else in Western Europe except for the Seine around Paris and the Rhine around Cologne.¹⁹

The marshes weren’t barren, of course. There were sedges and rushes, and enough grass to make haystacks; obstinate pagans went out to cut hay on a fine, still Sunday when the saintly Anskar was preaching and missioning, and saw their disrespectful work go up in spontaneous fire as punishment.²⁰ The hides from their cattle became leather and, conveniently, sea lavender grew on the marsh, its root used for tanning. The salt peat made sod for the walls of houses. There was common grasswrack, the sea grass whose ashes produce a salt to preserve meat and whose stems, up to a metre and a half long, had a dozen uses: stuffing mattresses, making the seats for chairs, thatching houses, lining ditches, even as a kind of woven fence that would keep back the drifting sands. It made excellent litter for the animals in the byre and, dug into the ground of the terpen afterwards, it fertilized the gardens. Turnips grew there alongside broad beans and oilseed rape, barley and a few oats.²¹

The people on the terpen couldn’t produce everything they wanted, not even everything they needed. They couldn’t make wine and they couldn’t produce much grain, but they wanted both; they were prepared to ship out down the rivers to Alsace for wine and as far as Strasbourg for grain. They also needed timber for the roof frames of their sod houses. So they had to do business to get necessities: to send out anything they could produce from animals – parchment and bone, leather and wool, cloth woven from the wool – in order to buy what they couldn’t grow. They already knew all about adding value to their basic products, starting a kind of Frisian brand; one farm close to modern Wilhelmshaven kept two different breeds of sheep for two different kinds of wool so as to make all kinds of fine cloth.²²

The terpen must have worked a little like islands, holding people’s fierce local loyalties. They seem isolated but they are often full of sailors who have been away to everywhere. Frisians became famous for travelling, and for their women who waited behind and their constancy. There is a ninth-century poem in The Exeter Book that turns Frisian marriage on the terpen into a moral example, and perhaps a report of a loving ritual. ‘He’s so very welcome, so dear to his Frisian wife when his boat is back,’ the poem says. ‘He’s the one who provides for her, and she welcomes him, washes his clothes dirtied by the sea and gives him clean ones. She gives him on dry ground all that his love could wish: the wife will be faithful to her husband.’

The poet’s realistic; he knows some women are constant, and some want novelty, the available stranger when the husband is away; indeed the laws of Frisia that Charlemagne codified suggest a tolerance for brisk infanticide to dispose of the evidence of indiscretion.²³ But he remembers the sailor, too. ‘He’s at sea a long time, always thinking of the one he loves, patiently waiting out the journey he can’t hurry. When his luck turns again he comes back home – unless he is sick, or the sea holds him back or the ocean has him in its power.’²⁴

The sea could kill, and yet it was the easy route: the connection, not the barrier. The network of Roman roads survived, but they were broken and rutted and hard work for a loaded waggon in many months of the year. The Roman system of posthouses was in place so you could change horses on a long ride, but it was a cumbersome business compared with going by sea or river; and it was slower, and often less safe than the water. It is true there were pirates, but the reason pirates went on working the North Sea from Roman times to the seventeenth century was that they knew civilians were always willing to risk being raided for the ease of a sea crossing. There were also storms, but there were prayers and saints to calm them: the lives of saints tell so many stories of miracles at sea that they tend to prove the general terror of foul weather. Believers clung to the Church as sailors cling to a ship, and ships came to be signs of faith.

Even saints knew that no voyage was ever quite certain. Willibrord was a missionary, the first Bishop of Utrecht, and he had thirty convert boys to ship down from Denmark to Frisia. He made sure to baptize them all before setting out, because of the ‘dangers of such a long sailing and the attacks of the ferocious natives of those parts’ and the awful possibility that they might drown and be eternally damned despite all his good work.²⁵ The prefect Grippo, returning from a diplomatic mission to some kings in England, faced the violence of the storm and learned it was best to let the ship drift until there was calm. He suffered a night of furious wind and crashing waves, shipping water, and he had to wait for the sun to rise before he could see the old-fashioned lighthouse up ahead, probably the Roman tower at Boulogne that Charlemagne had rebuilt. Only then did he hoist again the sail that must have been lowered hours before.²⁶

All this was a gloriously alarming muddle of the practical and the fearful. On one hand fresh water was supposed to be Godly and good, renewing and refreshing life itself, while salt water was a desert, a cliff off which ships could fall; it was an abyss where Leviathan lived with other terrible creatures, ‘a king over all the children of pride’, according to the Book of Job, ‘made without fear’ and able to make ‘the deep boil like a pot’, with terrible teeth, breath to kindle coals and the power to lay a trail of phosphorescent light behind him on the water.²⁷ On the other hand, you could always hunt the smaller terrible creatures and eat them; St Bridget of Kildare fed her guests fresh seal, the same St Cuthbert who was famously kind to ducks sometimes existed on the flesh of beached dolphins, and St Columba prophesied the coming of a gigantic whale off the island of Iona but said God would protect his fellow monks from its terrible teeth. He did nothing to save the whale.²⁸

For Christians, as you can see in the vivid pages of some Psalters designed on Frisian territory, the land was almost Heaven and the sea was Hell, full of beasts and tortures and also temptations to sin; the coastline was a kind of battleground between the two, and inland was where good people could get on with their industrious and virtuous lives.²⁹ Sea was where holy men might go and put away the rudder and trust to God, knowing they were at risk. The sea, after all, was where pagan heroes went, where unfamiliar and unholy things abounded. But it was also the Frisians’ workplace, and they saw no reason to rush conversion to Christian attitudes. They were used to working together on their boats so they held to the old view that shipping out implied all sorts of virtues: loyalty, trust and competence.

They used anchors on their boats, as the Romans did, with heavy chains to pull them up and let them down in shallow water or on the sands. Once the anchor was raised, their flat-bottomed boats might still be settled in the sand, so they carried a gaff in the shape of a metal V at the end of a wooden pole to push themselves clear.³⁰ The main power was muscle power, rowers sitting on sea chests, which was the kind of power a captain could control; but there were also sails to help out the oarsmen, and since nobody could yet tack into a headwind, each journey had to wait for the right wind to blow the ship forwards. Boniface shipped out from England on his mission to convert the Frisians in 716, clambered up the side of a quick ship with the sailors bustling about and had to wait for the great sail to be puffed out with the right winds;³¹ or so Willibald says in his life of the saint. Willibald refers to the sail as ‘carbasa’ in the Latin, which more usually is a word for linens, even though we know most sails were sewn from lengths of woven wool. When Boniface’s body was shipped over the Aelmere on a more ordinary ship with ‘swelling sails’, the word used this time was ‘vela’, the more common word.³² Did fast ships need a different kind of sail?

Since the sea was not a barrier like the land, the world had a different shape. We would find it hard to recognize.

Suppose you crossed from Domburg to the trading port at Ipswich on the east coast of England, newly opened in the seventh century; your cargo might be pots from the Rhineland or glass or the hefty lava quernstones used for grinding grain in mills.³³ Stand on the banks of the River Orwell and look out at the world. If you think in terms of the time it takes to get to places, then Bergen in Norway is closer than York in England, even if your boat to Bergen depends on the muscle power of rowers; but York is only 340 km away by road on modern maps while Bergen is 510 km by sea. The coast of Jutland is closer, and better connected, than an English Midlands city like Worcester. You could be over the water and in the port of Quentovic, on the border between modern France and modern Belgium, in half the time it took to get to London overland; and if you had a faster ship, under sail, you could be in Jutland sooner than London. Travel by land had none of the sea’s advantages, such as the prevailing summer winds that virtually blow a Norseman home from around Calais; and at sea, despite the habit of clinging to the shore for the sake of navigation and being able to sleep on dry land at night, it was actually safer out in the open, away from the shoals and currents of the English coast.³⁴

It was easy for Scandinavians to be in York, Frisians in Ipswich, Saxons in London, and the fact was so unremarkable that it is hardly recorded. You didn’t need a harbour to land because you could beach a flat-bottomed boat on any stretch of sand; so the great customs ports like Quentovic were tucked into estuaries or else, like Dorestad, upstream on the Rhine. More, going off to sea did not always mean building a huge ship and recruiting a large crew, although having more men who could fight off raiders was often a good idea; there was no need, on the coastal runs, to share the costs and risks because they were not that high; an individual could do it for himself.

A sea change, if you like, was coming.

All through the seventh and even the eighth centuries, much of the business across the sea looked like ceremony, a way of moving around all those luxurious goods that a king, chief or emperor needed to ensure alliances, make friends and keep his men loyal. Traders were more escorts than dealers, transporting bribes and rewards, moving goods so someone else could give them away. Again, the Frisians were different. They had their own tastes and they moved goods to satisfy themselves. From the sixth century, they were buying pots for their own use from the Frankish kingdom to their south, simply because they liked them.³⁵ They bought jewellery from England and Scandinavia, and they got their weaving battens made out of whalebone from Norway. They may even have kept souvenirs: among their stashes of useful coins are pretty cowrie shells from the Red Sea.³⁶

Their kind of business required money: not a heap of gold and silver wealth that would go well in your grave, but live money, coins to use in trade. All through Gaul the only point of coins was an easy way to ship gold about. In England it took two hundred years after the Romans left before coins were used as money again. There were no mints at all east of the Rhine until Regensburg, and that mint produced very little.³⁷ It was the Frisians who reinvented useful money, and taught their ideas to the Franks under Charlemagne.

For gold had always been about power, ceremony, buying support and paying taxes: the currency of politics. Romans used it that way, the great landowners paying into the state and a bit of subsidy flowing back (as usual) to the people who needed it least, the great landowners. In the sixth century, gold still flooded into state coffers – the ones belonging to the Frankish kings and no longer the Roman emperors – but it hardly even dribbled back out; it was money that did not circulate, fit only to be kept, counted, buried and, quite usually, stolen.³⁸ Gold was often a gift, not always entirely voluntary, which showed how and where you fitted: who were your allies, who were your masters. You did not necessarily get anything in return: you couldn’t give gold to a church and expect a measure of salvation. You certainly didn’t get a load of grain or a shipful of amber or a posse of slaves for your gold; the return was wonderfully abstract, an idea of yourself. In early medieval epics, its commonest form is not even coins: it is small gold rings, against which the poets measured any other gifts in circulation, however substantial, and ultimately the value and standing of the people who got them and gave them.³⁹

When the big Roman estates folded and the diminished cities were no longer the focus of life, all of a sudden something smaller, less valuable, more flexible than gold was required: a currency of trade. It was not just the long-haul international trades which needed a token of value that made sense at both ends of the voyage and everywhere in between. Peasant farmers taking their goods into local markets needed some way to buy and sell with coins;⁴⁰ they couldn’t simply go home with more of the same kind of grain or cabbage or beans they’d taken to market, even if that was what their neighbours had to sell; they needed a way to buy cloth or pots, things produced in other places and by other kinds of people, and in any case there was a limit to the beans or cabbage or grain that the cloth and pot merchants wanted.

Silver worked: small, thick silver coins that were often minted locally. The Frisians minted them with the old god Wotan on one side, with spiked hair, a drooping moustache and eyes that stare out like goggles; and on the other side a serpentine kind of monster with clawed feet and a high tail. The Anglo-Saxons in England imitated the Frisians, and put a creature like a porcupine on their silver, or sometimes a king.⁴¹

These silver deniers were scarce in all the wide Frankish territory until the Franks grabbed Frisia and its mints in the 730s. After that, mints were most common along the Frankish route into Frisia; even from around 700 CE there are deniers scattered about the stops on that trade run. The most commonly found ones were struck in Frisia, although it is not always easy to tell them from the Anglo-Saxon kind made across the water. The record buried in the ground suggests that Frisia was the centre if not the home of practical cash.⁴² But it wasn’t the countryside, the inland territory, which had money; it was the trading ports. The sands at Domburg gave up almost a thousand of the early pennies, the sceattas,⁴³ and from there the coins went where merchants went: to the Frisians’ cousins and their trading partners in England, but also all the way up the run of the Rhine as well as south to Marseilles and the Mediterranean. In Aquitaine Frisian coins were much preferred to the debased money coming from what is now France.

The silver had to come from somewhere else since there were no mines in Frisia. To be able to manufacture this money, the Frisians had to make money in the first place and they got it by selling to the Franks, who wanted slaves and furs and fish and Frisian cloth, especially cloth of many colours. The white, grey, red and blue kinds were expensive and much appreciated in the East – so Charlemagne thought when he gave some to the Caliph of Baghdad, along with fierce and agile dogs for catching lions and tigers.⁴⁴ Frisian cloaks were mostly for the mass market, given away by the Emperor Louis the Pious to the lower orders in his court at Easter, while nobles got belts and silks, and the grooms, cooks and scullions got linen, wool and knives.⁴⁵

The Frisians were notorious for cashing in on style; in Gaul, when shorter tunics were in fashion, the Frisians sold them but at the price of the longer, old-fashioned kind, and the Emperor had to intervene.⁴⁶⁴⁷offer, which was corn, wine, metal, pottery and glass; and the rest of the silver, whatever form it took, could be turned into their own coins. It was not just that trade gave coins a use; the Frisians would not have had the metal to make them in the first place without trade.