Tullus Hostilius was the legendary third king of Rome. He succeeded Numa Pompilius. He was one of the six Etruscan kings that ruled Rome. He ruled from 673 to 642 BC. Unlike his predecessor, he was known to be a warlike king. He was the grandson of Hostus Hostilius, who had fought with Romulus and died during the Sabine invasion of Rome. His successor was Ancus Marcius.