In his autobiography, Edward Gibbon described how the idea first came to him of writing The Decline and Fall of the Roman Empire:

By the ‘Temple of Jupiter’, Gibbon meant the church of Santa Maria in Aracoeli on the Capitoline, which antiquaries of the time thought stood directly on the site of the temple of Jupiter Capitolinus, seat of the Roman state religion. The image of the authority of the Christian Church replacing that of the Roman Empire is a striking and memorable one but, had he known it, Gibbon, instead of going to Rome, could have come to the scene of our conference at York, or to its sister legionary fortress at Caerleon in south Wales, the Roman Isca, for both York Minster and the church of St Cadoc at Caerleon overlie the Principia of their Roman Fortress, where the legionary standards were displayed, and the images of the Roman Emperors venerated.

Christianity in Late Roman Wales

It is of course something of an anachronism to speak of ‘Roman Wales’, for that can only be shorthand for something like ‘the mountainous western parts of the province of Britannia Prima’. Yet it was in the immediate post-Roman period that a geographical entity which was to become recognizably Welsh was to develop. It was Christian and literate, first in Latin and in time in Welsh. We can now see that the beginnings of that process were already in place in late Roman times, at least in the two urban centres (in the very broadest sense) of Caerleon (Isca) and Caerwent (Venta Silurum) in the lowland area of south-east Wales.

Isca, the fortress of Legio II Augusta, stands at the highest convieniently navigable point on the River Usk. From the Roman bridge, whose timber successors remained on the same site until 1806, a road ran eastwards to Caerwent and ultimately to Gloucester below a steep wooded ridge which was the site of one of the major cemeteries of the fortress.