 Slavery is the state of being in the absolute or arbitrary power of another. On Locke’s definition of slavery, there is only one rather remarkable way to become a legitimate slave. In order to do so, one must be an unjust aggressor defeated in war. The just victor then has the option to either kill the aggressor or enslave them. Locke tells us that the state of slavery is the continuation of the state of war between a lawful conqueror and a captive, in which the conqueror delays taking the life of the captive, and instead makes use of him. This is a continued war because if conqueror and captive make some compact for obedience on the one side and limited power on the other, the state of slavery ceases and becomes a relation between a master and a servant in which the master only has limited power over his servant. The reason that slavery ceases with the compact is that “no man, can, by agreement pass over to another that which he hath not in himself, a power over his own life” (Treatises II.4.24). Legitimate slavery is an important concept in Locke’s political philosophy largely because it tells us what the legitimate extent of despotic power is and defines and illuminates by contrast the nature of illegitimate slavery. Illegitimate slavery is that state in which someone possesses absolute or despotic power over someone else without just cause. Locke holds that it is this illegitimate state of slavery which absolute monarchs wish to impose upon their subjects. It is very likely for this reason that legitimate slavery is so narrowly defined. This shows that the chapter on slavery plays a crucial role in Locke’s argument against Sir Robert Filmer and thus could not have been easily dispensed with. Still, it is possible that Locke had an additional purpose or perhaps a quite different reason for writing about slavery.