Yet the security and prosperity of London are not at this early date so certain. Like an organic being London grew and developed outwards, always seeking to incorporate new territory, but it also suffered periods of weariness and enervation when the spirit of the place hid its head. We may find tokens of just such a change by those same eastern banks of the Walbrook where the clerks of the empire tossed their pens into the water. Here was discovered, in 1954, the remains of a temple devoted to Mithras and subsequently to other pagan deities. It was not uncommon for Roman Londoners to embrace a variety of faiths; there is good evidence, for example, that the beliefs of the original Celtic tribes were incorporated into a peculiar Romano-Celtic form of worship. But the Mithraic mystery cult, with its rites of initiation and the secrets of its arcane ritual, seems at least in theory to presage a more disturbed and anxious city.
The most resourceful period of Roman London lay in the years spanning the first and second centuries, but these were followed by an uneven period combining development and decline. That decline was in part associated with the two great titular spirits of London, fire and plague, but there was also a steady alteration of imperial rule as the empire itself weakened and decayed. In approximately AD 200, some fifty years before the temple of Mithras was erected, the great wall was constructed around London. It speaks of an age of anxiety, but the very fact of its erection suggests that the city still had formidable resources of its own. Large areas within the wall were unoccupied, or used for pasture, but there were fine temples and houses in the more fashionable district close to the river. The first London mint was established in the third century, testifying once again to the city’s true nature. In that century, too, a riverine wall was constructed to complete the city’s defences.
There were of course, in the passages of this long history, periods of turbulence and warfare. Many have gone unrecorded, but one or two powerful incidents survive. The darkness breaks and a scene presents itself, frozen for a moment, throwing into further confusion and mystery the historical process of which it is a part. A Roman leader named Allectus sailed to Britain in order to put down a local rebellion; having defeated the rebels he set up his headquarters in London. A Celtic chieftain, Asclepiodotus, in turn marched against the imperial victor; outside the city there was a great battle in which the British were successful. The remaining Roman troops, fearing massacre, fled within the walls and closed the gates. Siege engines were brought, and a breach was made in the defences; the Celts poured in and the leader of the last legion begged for mercy. It was agreed that the Romans could withdraw and take to their ships but one tribe or group of tribesmen reneged on the agreement: they fell upon the Roman soldiers, decapitated them in ritual Celtic style and, according to the narrative of Geoffrey of Monmouth, threw their heads into “a brook in the city … in Saxon, Galobroc.” Many skulls were, in the 1860s, found in the bed of the long-buried Walbrook River. The rest is silence.
But we cannot from the evidence of this single anecdote assume that the history of London is one of warring tribes against a common Roman enemy. All the evidence suggests otherwise and instead intimates a degree of mingling, maintained by mutual trade, that encouraged an almost unbroken continuity of commerce and administration. There would by now be something of a London type, perhaps with that particular “muddy” complexion which became characteristic in later years. No doubt the citizens spoke a Latin patois which included native elements, and their religious beliefs would have been equally mixed and idiosyncratic. The Mithraic temple is only one example of a mystery religion-predominantly the reserve of merchants and professional administrators-but the Christian faith was not unknown. In AD 313 a certain Restitus attended the Council of Arles in his capacity as Bishop of London.