1066 and all that: a millennium of Normans

On this 950th anniversary of the Battle of Hastings, what English chiffrephile could resist a look at the numbers of our Norman cousins over the intervening period – and specifically at the time of the Conquest? The topic has come up with surprising regularity on discussion boards and query sites, understandably as the relative resources of England and Normandy cannot have been without relevance in the events of 1066 and the subsequent unravelling of the joint realm.

It has long been apparent that England was the more populous of the two states whose half-century-old dynastic engagement erupted in the conflict that brought down the Anglo-Saxon monarchy. But by how much? Modern England's 130,000 sq km compare favourably to Normandy's 30,000, while England's 55 million inhabitants now dwarf Normandy's 3.3 million. But the magnitude of today's population gap is of comparatively late origin: when we get our first semi-official figures in the 18th century the Normandy region contained about 30% as many people as its now far faster-growing neighbour across the Channel, and there seems no likelihood that England's lead had ever been greater.

England's population history is now relatively well-documented, with the painstaking work of the Cambridge group showing a near-doubling from 2.8 million in 1541 to 5.2 million by 1700. Going back further we have the 1377 return of taxable adults, indicating a total of 2.3 million or more after the worst ravages of the Black Death, depending on the rate of exemption and evasion. And for the 11th century we of course have the Conqueror's own Domesday survey, variously thought to indicate a population of 1½-2½ million, nowadays generally taken to be around or above the middle of the range since Sally Harvey's identification of the large numbers unrecorded for their lack of manorial obligations.

For Normandy we have little to go on beyond the first French censuses indicating 2.5-2.6 million in the early 19th century, and various returns of 1½-2m in the 18th – the latter certainly underestimates as for the kingdom as a whole, but sufficient to suggest an adjusted 1.65 million around 1700 for the then généralités of Rouen, Caen & Alençon (a figure that as we shall see is itself likely to be too low). Before then there are isolated figures for hearths or tax receipts.

But it is possible to identify a likely trend extending back into the Middle Ages. Today's Normandy covers just over 5½% of the area of metropolitan France, with a similar share of national population. Two centuries ago its population share was significantly higher, as much as 8½% in 1801-11. The 18th-century returns suggest a proportion nearer 7½%, perplexingly as there seems no other evidence of exceptional intervening regional growth, recorded births and deaths instead indicating a slight relative decline from at least the 1760s: part of the answer may lie in the inclusion of some south-eastern districts in the généralité of Paris, or in fuller early census reporting than elsewhere.

What of the earlier period? Here Normandy's share of France's urban population seems to offer a guide to the likely trend. The contribution of Rouen, Caen and le Havre fell steadily over the modern period relative to 35 principal French cities, from 10% in 1550, 8½% in 1650 and 7½% in 1750 to 7% in 1800, 5¾% by 1850 and only 4¼% in 1900 – the abruptness of the 19th-century fall reflecting rapid growth in Paris, Marseille, Lyon and the country's other large industrial cities. Removing Paris from the calculation gives 13% in 1550, 11% in 1700, 10¼% in 1800, 9½% in 1850 and 8% in 1900, despite Le Havre's late start and rapid 19th-century growth.

While heavily influenced by Rouen's relative eclipse from the 16th century and not in itself conclusive – the 18th-century totals indeed suggest a contrary trend, which may in turn indicate a provincial under-estimate – the urban evidence strongly suggests that Normandy's share of French population in earlier centuries was at least no smaller than in 1700 even if the region experienced relatively slow urbanisation to 1830, which is possible as maritime activity shifted to the west coast and higher government functions became more centralised in Paris.

Going back still further, the hearth count of 1328 – after the 1315-17 famine but twenty years before the Black Death – yields around 300,000 hearths (usually considered to approximate to households) in the baillages of Rouen, Caen, Caux, the Contentin and Gisors, indicating a population of around 1½ million out of the 18 million estimated for the area of modern France. A similar figure is implied by the tax return of 1221, or possibly rather more again allowing for exempt groups. The 14th-century estimate suggests a Norman share of a twelfth of France, the 13th-century one a tenth or more as it seems improbable that French population remained unchanged in the interim.

What then of 1066 itself? Here we need to venture further assumptions about French and wider European population growth. It is generally considered that European population roughly doubled over the 11th-13th centuries, with faster increases in the east, centre and north, slower in the south and particularly the Balkans. For France with its Mediterranean attachments and Roman past, growth is likely to have been at best no higher than the continental average, indicating a population in 1066 of around ten million for today's area. This in turn indicates a Norman population of 830,000 or more, perhaps in excess of a million, to which we might add an allowance for Norman emigration in the following centuries.

Taking the population of Harold's England as around two million, Normandy is thus likely to have contained two-fifths to half as many inhabitants. So how did William win given that after a quarter-century of growing Norman influence under the confessor little is likely to have separated the two sides in battle tactics or technology? Part of the answer doubtless lies in his good fortune in facing an enemy who had only three weeks earlier fought off one dangerous invader and had then had to march 250 miles south – mere weeks after a 200-mile march north – to confront another. Harold's force should have been the more numerous, but on the fatal day barely matched his adversary's, with the respective armies amounting to under one per cent of Normandy's population and 0.4% of England's. Perhaps Harold erred in being too ready to give battle when he might have drawn the challenger from his coastal beachhead; but perhaps time was of the essence as many of his best warriors approached exhaustion.

Perhaps more importantly, the exercise suggests why England was so important to William – and so valuable to his heirs that they preferred to keep their new land as the seat of their power, even at the cost to their Angevin successors of losing Normandy itself to the rising French crown after only 138 years of on-off cross-Channel personal union. At a stroke the House of Robert had tripled the people and resources under its rule, winning in the process a territory free of even nominal obligations to the French crown.

For Normandy, 1066 was a high-water mark in the duchy's meteoric ascent, before incorporation as a mere French province and centuries of sluggish growth in contrast to the later explosion of English population, production and commerce. For the Anglo-Saxon state it was of course a more dramatic end, whose consequences remain with us to this day even as England prepares to close another chapter in its often prickly relationship with the Continent.