You can find them here and there, scattered across England: the small green mounds, the hillocks and filled-in ditches, the hints of straight lines that once cut through the landscape. Just beneath the long grass lies the rich silt, piled up by the wind or washed in by the rain in the 62 years since the coronation of Queen Elizabeth I I. In the 177 years since Victoria took the throne. The 949 years since a determined William of Normandy landed on the English shore. The 1,418 years since St. Augustine came to Canterbury, a prayer book in his hand.
Dig down in any of those places—from Exeter up to Wallsend, on one diagonal of the English countryside, and Ambleside down to Dover, crisscrossing on the other—and underneath the present grass and brambles, down past the thousand years of smoothing silt, you’ll discover a seam of ash mixed with a dark, thick loam. And beneath that, a solid layer of fired brick and quarried stone, mortared with Roman concrete. It is a deep truth of England, of most of Western civilization, that if you dig down deep enough, you always come at last to the hard remnants of ancient empire. Rome is the buried foundation on which the weight of the world still rests.
As Guy de la Bédoyère points out here, Britain was not unknown to the ancient Mediterranean world. In the fourth century b.c.—while Rome was still struggling to expand on the Italian peninsula—the explorer Pytheas sailed from his base in the Greek colonial city of Massalia (now Marseilles) to circumnavigate Brettaniai. The tin mines of Devon and Cornwall became vital to Europe only later, after the exhaustion of Spanish tin; but even by the third century b.c., traders were hauling British tin across to Gaul—floating it down the Rhône to the Mediterranean and on to Rome, which had become the gravitational center of the known world, pulling everything toward it.
Only in 55 and 54 b.c. did Rome pay serious attention to the island, when Julius Caesar led his legions in a pair of voyages across the English Channel. He had some excuse, as the Britons had been aiding the Belgic tribes he was fighting in his conquest of Gaul. Still, even Caesar’s own account in his Commentaries makes the invasions seem less a military endeavor than a star turn, undertaken mostly for their effect back in Rome: Caesar goes to exotic Britain!
Caesar’s expeditions did, at least, manage to prove that even lands as distant as first-century Britain were already influenced by the sheer presence, the weight, of Rome in the ancient world. Mandubracius, a threatened prince of the Celtic tribe of the Trinovantes (in what is now Essex), had fled across the channel to seek Roman protection and aid. Caesar would use the second of his attacks on Britain to install the grateful Mandubracius as Trinovantian king—and, of course, to demand tribute and hostages, since Caesar was doing what the Romans always did on the edges of their land: stealing a little booty, choosing sides, and encouraging clients and allies.
However often that technique eventually resulted in imperial expansion, it was typically prompted by a more conservative impulse simply to preserve existing possessions. The Romans used neighboring buffer states partly as a bulwark against raids but even more to provide the tripwire system they needed to protect the empire. The actual extent of Roman defense-in-depth, in place of fortified borders, is much disputed by classicists; but where it worked, the Romans could maintain their empire on the relative cheap by garrisoning rapid-response legions in the provincial cities, where their military presence would also serve the purpose of discouraging revolt.
In the case of Britain, the client system worked, more or less, for 90 years. Although Caesar’s grand-nephew Augustus threatened invasion three times, he never carried through on his threats—at least partly because he didn’t need to. The various tribes of Britons were well caught in the orbit of Roman trade, with the island providing Rome more cash in import customs and duties than Rome could get by conquering the Britons and taxing them (or so the geographer Strabo claimed at the time).
Things started to break down, however, in the new century, as political upset and intra-Briton wars caused a decline in trade. Three years after Caligula’s peculiar failure to invade—leaving his soldiers to gather seashells on the shores of Gaul—Claudius pressed forward in a.d. 43, sending approximately 40,000 men (four legions and their auxiliaries) to calm the island’s turmoil. The Romans wouldn’t leave for another 367 years.