rale super qualuor
libros Sententiarum_, iv. xv. I; and see Carletus, _Summa Angelica_,
q. ccxii.]

It must not be forgotten that we are dealing purely with theory.
In fact the Church did an inestimable amount of good to the servile
classes, and, at the time that Aquinas wrote, thanks to the operation
of Christianity in this respect, the old Roman slavery had completely
disappeared. The nearest approach to ancient slavery in the Middle
Ages was serfdom, which was simply a step in the transition from
slavery to free labour.[1] Moreover, the rights of the master over
the slave were strictly confined to the disposal of his services; the
ancient absolute right over his body had completely disappeared. 'In
those things,' says St. Thomas, 'which appertain to the disposition
of human acts and things, the subject is bound to obey his superior
according to the reason of the superiority; thus a soldier must obey
his officer in those things which appertain to war; a slave his master
in those things which appertain to the carrying out of his servile
works.'[2] 'Slavery does not abolish the natural equality of man,'
says a writer who is quoted by the _Catholic Encyclopaedia_ as
correctly stating the Catholic doctrine on the subject prior to the
eighteenth century, 'hence by slavery one man is understood to become
subject to the dominion of another to the extent that the master has
a perfect right to the services which one man may justly perform
for another.'[3] Biel, who lays down the justice of slavery so
unambiguously, is no less clear in his statement of the limitations
of the right. 'The body of the slave is not simply in the power of the
master as the body of an ox is; nor can the master kill or mutilate
the slave, nor abuse him contrary to the law of God. The temporal
gains derived from the labour of the slave belong to the master;
but the master is bound to provide the slave with the necessaries of
life.'[4] Rambaud very properly points out that the reason that the
scholastic writers did not fulminate in as strong and as frequent
language against the tyranny of masters, was not that they felt less
strongly on the subject, but that the abuses of the ancient slave
system had almost entirely disappeared under the influence of
Christian teaching.[5]

[Footnote 1: Wallon, _op. cit._, vol. iii. p. 93; Brants, _op. cit._,
p. 87.]

[Footnote 2: II. ii. 104, 5.]

[Footnote 3: Gerdil., _Comp. Inst. Civ. I._, vii.]

[Footnote 4: