Mummius stepped up to a brass hook cast as the heads of Cerberus and mounted in the wall. He hooked his shoes over two of the heads and hung his belt in the open jaws of the third. He pulled the heavy chain mail over his head and set about unbuckling leather straps. 'But you have to admire such feats of plumbing. There's a natural hot spring that comes out of the earth at just this spot; that's why the first owner chose to build here – that, and the view. When Orata rebuilt, he designed the pipes so that some of the pools are piping hot, while others are mixed with cool water from a different spring up the hill. You can pass from the coolest to the hottest and back again. In winter some of the rooms in the house are even heated by water from the hot spring, piped under the floors. This changing room, for example, is kept warm all year long.'

'Most impressive,' I agreed, pulling my undertunic over my head. I started to place it in one of the coffers in the wall but Mummius intervened. He called to an old, stooped slave who stood at a discreet distance across the room. 'Here, take these and have them washed,' he said, indicating my things and Eco's and pulling his own tunic over his shoulders. 'Bring back something suitable for an audience with your mistress.' The slave gathered up the garments and studied us for a moment, estimating our sizes, then slunk from the room.

Naked, Marcus Mummius looked something like a bear, with big shoulders, a broad middle and dense swirls of black hair all over his body, except where he was marked by scars. Eco seemed particularly intrigued by a long slash that ran across his left pectoral like a cleared furrow in a forest.

'Battle of the Colline Gate,' Mummius said proudly, looking down and pointing to the scar. 'Crassus's proudest moment, and mine. That was the day we retook Rome for Sulla; the dictator never forgot what we did for him. I was wounded early in the day, but fortunately it was on the left side, which allowed me to go on using my sword arm.' He mimed the action, bolting forward and swinging his right arm, causing the rather stout sword between his legs to swing heavily back and forth as well.