timelets

And though he owned numberless silver mines, and highly valuable tracts of land with the labourers upon them, nevertheless one might regard all this as nothing compared with the value of his slaves; so many and so capable were the slaves he possessed, — readers, amanuenses, silversmiths, stewards, table-servants; and he himself directed their education, and took part in it himself as a teacher, and, in a word, he thought that the chief duty of the master was to care for his slaves as the living implements of household management.

7 And in this Crassus was right, if, as he used to say, he held that anything else was to be done for him by his slaves, but his slaves were to be governed by their master. For household management, as we see, is a branch of finance in so far as it deals with lifeless things; but a branch of politics when it deals with men.

--- Plutarch, Lives. Crassus: 6-7.
https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Plutarch/Lives/Crassus*.html