It was a low dungeon, built of that brick which we still recognise as of Roman manufacture, in the foundations of what had been the eastern tower of the ancient fortification. The old pile had been badly preserved by the Saxon conquerors, but it had been built of that solid architecture which seems almost to defy the assaults of time, and which in some cases, after fifteen centuries, preserves all its characteristics, and promises yet to preserve them, when our frailer erections lie crumbled in the dust.