This wall, which is by some supposed to have been built by Constantine the Great, and by others by his mother Helena, was probably not erected till the time of Valentinian I. about the year 368. Britain had been reduced to very great misery, by the joint attacks of the Scots, Picts, Attacots, Saxons, and Franks; and the Romans, till the arrival of Theodosius the Elder, were defeated in several engagements: but that General having routed some parties of the enemy, entered the city of London in triumph. And we are told by _Am. Marcel, lib. 27._ that Theodosius, by repairing some cities and castles, and fortifying others, left every thing in so good a situation, that peace was preserved in Britain till the departure of the Romans in the reign of the Emperor Honorius. Dr. Woodward, in the year 1707, had an opportunity of narrowly observing its fabrick and composition, by a part of the wall near Bishopsgate being pulled down, to make way for new buildings; and this learned antiquary observes, that “From the foundation, which lay eight feet below the present surface, quite up to the top of the oldest part, which was in all near ten feet, it was compiled alternately of layers of broad flat bricks and rag-stones. The bricks lay in double ranges, and each brick being but one inch and three tenths in thickness, the whole layer, with the mortar, exceeded not three inches. The layers of stone were not two feet thick of our measure. It is probable they were intended for two of the Roman, their rule being somewhat shorter than ours. To this height the workmanship was after the Roman manner, and these were the remains of the ancient wall. In this it was very observable, that the mortar was so very firm and hard, that the stone itself as easily broke. It was thus far, from the foundation upwards, nine feet in thickness. The above broad thin bricks were all of Roman make, and of the very sort we learn from Pliny, that were in common use among the Romans. Measuring some of these (says Mr. Woodward) I found them seventeen inches and four tenths in thickness, and eleven inches and six tenths in breadth.