According to the legend, Romulus and Remus were the sons of Rhea Silvia, the daughter of King Numitor of Alba Longa. Alba Longa was a mythical city located in the Alban Hills southeast of what would become Rome. Before the birth of the twins, Numitor was deposed by his younger brother Amulius, who forced Rhea to become a vestal virgin so that she would not give birth to rival claimants to his title. However, Rhea was impregnated by the war god Mars and gave birth to Romulus and Remus.