Tullus Hostilius was the legendary third king of Rome. He succeeded Numa Pompilius and was succeeded by Ancus Marcius. Unlike his predecessor, Tullus was known as a warlike king who, according to the Roman historian Livy, believed the more peaceful nature of his predecessor had weakened Rome. It has been attested that he sought out war and was even more warlike than the first king of Rome, Romulus. Accounts of the death of Tullus Hostilius vary. In the mythological version of events Livy describes, he had angered Jupiter who then killed him with a bolt of lightning. Non-mythological sources on the other hand describe that he died of plague after a rule of 32 years.

The king of Rome was the ruler of the Roman Kingdom. According to legend, the first king of Rome was Romulus, who founded the city in 753 BC upon the Palatine Hill. Seven legendary kings are said to have ruled Rome until 509 BC, when the last king was overthrown. These kings ruled for an average of 35 years.