Oath of the Horatii (1784), by Jacques-Louis David

In Roman mythology, the Horatii were a set of male triplets from Rome. During a war between Rome and Alba Longa during the reign of Tullus Hostilius (approx. 672-642 B.C.), it was agreed that settlement of the war would depend on the outcome of a battle between the Horatii and the Curiatii. The Curiatii were a set of male triplets who were from Alba Longa and of the same age as the Horatii.

In the battle, the three Curiatii were wounded, but two of the Horatii were killed. The last of the Horatii turned to flee. The Curiatii chased him, but because they were wounded became spread out from one another, which allowed the Horatii to slay them one by one.

When the victorious Horatii returned carrying the spoils of victory, his sister cried out in grief because she realized the Curiatii she had been engaged to was dead. The Horatii killed his sister, proclaiming, "So perish any Roman woman who mourns the enemy." For the murder, he was condemned to death but was saved when he appealed to the people.

The legend might have been used as the reason why the condemned in Rome were allowed to appeal to the populace.

The main source of information regarding this tale is the "Ab urbe condita" by Titus Livius

The Horatii is also the name of a rock band from England.