DIAT, a name given by the Arabs to the punishment of retaliation. By the Mahommedan law, a brother, or the next relation of a murdered person, ought to take part against the murderer, and demand his blood in reparation for that which he has shed. Before the time of Mahommed, the Arabs had a custom of putting a freeman of their prisoners to death in lieu of every slave they lost in battle, and a man for every woman who was killed. But Mahommed regulated the laws of reprisal, directing in the Koran, that by the diat a freeman should be required for a freeman, and a slave for a slave. The Turks, probably in consequence of this law, formerly massacred almost all their prisoners of war, but they now content themselves with enslaving and selling them.