According to Roman mythology, Romulus founded the ancient city of Rome on April 21, 754 B.C.E. - the same day he killed his twin brother Remus.

Romulus and Remus were sons of Mars, the Roman god of war. Fearing that the newborn twins would someday overthrow him, Amulius, the king of central Italy, ordered a servant to kill them. Instead, the servant secretly put the babies in a basket and left them floating on the Tiber River. Rescued and raised by a she wolf, the two boys grew up to be highly respected warriors. Eventually they killed Amulius, and the new king rewarded the brothers with land. But they quarrled over how to use it, and Romulus killed Remus, founding Rome in his own name that same day.