Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
An arable estate of 200 -jugera- without orchards was estimated to require two ploughmen and six serfs: a similar estate with two orchards two plough-men and nine serfs; an estate of 240 -jugera- with olive plantations and sheep, three ploughmen, five serfs, and three herdsmen. A vineyard naturally required a larger expenditure of labour: an estate of 100 -jugera- with vine-plantations was supplied with one ploughman, eleven serfs, and two herdsmen. The steward of course occupied a freer position than the other slaves: the treatise of Mago advised that he should be allowed to marry, to rear children, and to have funds of his own, and Cato advises that he should be married to the stewardess; he alone had some prospect, in the event of good behaviour, of obtaining liberty from his master. In other respects all formed a common household. The slaves were, like the larger cattle, not bred on the estate, but purchased at an age capable of labour in the slave-market; and, when through age or infirmity they had become incapable of working, they were again sent with other refuse to the market.(6)
6. Mago, or his translator (in Varro, R. R., i. 17, 3), advises that slaves should not be bred, but should be purchased not under 22 years of age; and Cato must have had a similar course in view, as the personal staff of his model farm clearly shows, although he does not exactly say so. Cato (2) expressly counsels the sale of old and diseased slaves. The slave-breeding described by Columella (I. I. Italian History), under which female slaves who had three sons were exempted from labour, and the mothers of four sons were even manumitted, was doubtless an independent speculation rather than a part of the regular management of the estate--similar to the trade pursued by Cato himself of purchasing slaves to be trained and sold again (Plutarch, Cat. Mai. 21). The characteristic taxation mentioned in this same passage probably has reference to the body of servants properly so called (-familia urbana-).
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