I was contemplating the problem of the water mill again ten days later when Aratus brought the cook and his two young assistants into my library. Congrio was a heavy man; what good cook is not? As Lucius Claudius had once remarked, a cook whose creations are not so tempting that he stuns himself with stolen delicacies is not a cook worm having. Congrio was not Lucius's best cook — that post had been reserved for Lucius's house on the Palatine Hill in Rome, where he entertained his friends. But Lucius had not been a man to stint himself of culinary pleasures no matter where he went, and his country cook was more than skilful enough to delight my palate.

In the heat of the morning Congrio was already sweating. His two assistants stood to each side and slightly behind him, respectful of his authority.

I dismissed Aratus and asked Congrio and his helpers to step closer. I explained my intention to lend them to Claudia for the next few days. Congrio knew Claudia, because she had dined with his late master from time to time. She had always been pleased with his work, he assured me, and he was certain he would please her again and give me cause to be proud of him.

'Good,' I said, thinking it might help to smooth matters with the Claudii to render them this favour. 'There is one other thing…'

'Yes, Master.'

‘You will do your best for the Claudii, of course; you will obey Claudia, and Claudia's own cook as well, since you will be serving in her house.'

'Of course, Master; I understand.' 'And also, Congrio…' 'Yes, Master?' He wrinkled his fleshy brow. 'You will say nothing to embarrass me while you are in Claudia's service.'

'Of course not, Master!' He seemed genuinely hurt.

'You will not exchange gossip with the other slaves, or trade opinions of your respective masters, or pass along what you may perceive to be my opinions.'

'Master, I fully understand the proper behaviour of a slave who has been lent to a friend of his master.'