The Curia Hostilia was one of the original senate houses or "curiae" of the Roman Republic. It was believed to have begun as a temple where the warring tribes laid down their arms during the reign of Romulus. During the early monarchy, the temple was used by senators acting as a council to the king. Tullus Hostilius was believed to have replaced the original structure after fire destroyed the converted temple. It may have held historic significance as the location of an Etruscan mundus and altar. The Lapis Niger, a series of large black marble slabs, was placed over the altar where a series of monuments was found opposite the Rostra. This curia was enlarged in 80 BC by Lucius Cornelius Sulla during his renovations of the comitium. That building burned down in 52 BC when the supporters of the murdered Publius Clodius Pulcher used it as a pyre to cremate his body.

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.