The earliest known house for religious observance on the site of the present cathedral was a temple. In accordance with the usual practice of early founders, it is not surprising to find that the site selected for it was upon the highest spot of ground in the city. If we follow the accounts of old London, it would have been folly for the Romans to have erected an important building like a temple upon a lower level, which might have got swamped by an unusual rising of the tidal Thames. Apart from such consideration, it was not the Roman custom to debase, but rather to elevate as high as possible, any object they held in great reverence. It would form also a convenient centre to rally round in defence of any attack. In all accounts of the site of St. Paul's the writers have plenty to say about the three churches, but seldom, if ever, allude to the temple erected by the Romans. This is the more curious when etymologists have endeavoured to explain the affinity of Christian symbols to those of heathenism, showing how it was clearly impossible, and hardly to be expected, that pagan customs should be suddenly arrested and completely abolished, and an entire set of new observances introduced expressly for the new faith--Christianity. Such a sudden change could not, they contend, be thrust upon a people brought up to revere the old heathen deities and observe customs rendered sacred through superstition and countless ages. They required a gradual weaning, and this, so they say, was done by christianising the pagan symbols derived from nature-worship and adapting them to meet the requirements of the new faith,--symbols which, in course of time, became so clothed that their original significance was lost sight of.