A considerable number of people dwelt outside the walls of this, as of all the stations, sheltering under its walls, and relying on the protection of its garrison; the slope to the southward of Borcovicus shows many traces of buildings scattered all over it. On the northern side, the steep hill, massive masonry, and deep fosse would seem to have offered well-nigh insuperable difficulties to an attacking force such as then could be brought against the camp; yet not only here, but in all the stations whose remains yet survive, there is unmistakable evidence that more than once has the garrison been driven out by a victorious foe, to re-enter and occupy it again at a later period. And when we consider that the Wall and its forts were garrisoned by the Romans for a period extending over nearly three centuries, a period corresponding to the time from the reign of James I. to the present day, it becomes a matter of wonder, not that such was the case, but that such occurrences were not more frequent than the evidences seem to declare. In spite of all the hard fighting, however, the recreations of lighter hours would seem not to have been forgotten; on the north of the wall is a circular hollow in the ground, evidently a little amphitheatre, in which doubtless many a captive Briton and Pict played his part. On a little rise to the southward, called Chapel Hill, stood the temple where the garrison paid its vows to the various deities of its worship. Many remarkably fine altars found on this and other sites have been preserved, either at the fine museum at The Chesters, or at the Black Gate in Newcastle. One of the most striking is the altar to Mithras, the Persian sun-god, found in a cave near the camp, evidently constructed for the celebration of the rites connected with the worship of Mithras. The altar shows the god coming out of an egg, and surrounded by an oval on which are carved the signs of the Zodiac.