This aspect of the Slave was necessarily prominent in the Law. He was the one human being who could be owned. There were men in many inferior positions which look almost like slavery: there were the nexus, the auctoratus, the addictus, and others. But none of these was, like the slave, a Res. Potestatis verbo plura significantur: in persona magistratuum imperium…in persona servi dominium. The slave is a chattel, frequently paired off with money as a res. Not only is he a chattel: he is treated constantly in the sources as the typical chattel. The Digest contains a vast number of texts which speak of the slave, but would be equally significant if they spoke of any other subject of property. With these we are not concerned: to discuss them would be to deal with the whole law of property, but we are to consider only those respects in which a slave as a chattel is distinguished in law from other chattels. From their importance follows the natural result that the rules relating to slaves are stated with great fulness, a fulness also in part due to the complexity of the law affecting them. This special complexity arises mainly from five causes, (i) Their issue were neither fructus nor accessories, though they shared in the qualities of both, (ii) They were capable of having fructus of kinds not conceivable in connexion with other res, i.e. gifts and earnings, (iii) The fact that they were human forced upon the Romans of the Empire some merciful modifications of the ordinary rules of sale, (iv) They had mental and moral qualities, a fact which produced several special rules, (v) There existed in regard to them a special kind of interitus rei i.e. Manumission.