Tullus Hostilius was the 3rd of the 7 kings of Rome, following Romulus and Numa Pompilius. He ruled Rome from about 673-642 B.C. Tullus, like the other kings of Rome, lived during the legendary period whose records were destroyed in the fourth century B.C. Most of the stories we have about Tullus Hostilius come from Livius Patavinus (Livy), a Roman historian who lived in the first century B.C.
Hostus Hostilius and the Sabines
During the reign of Romulus, the Sabines and Romans were approaching each other in battle when a single Roman rushed ahead and engaged with a Sabine warrior who had similar ideas. The brash Roman was Hostus Hostilius, grandfather of Tullus Hostilius.
Though he did not defeat the Sabine, Hostus Hostilius was held up as a model of bravery. The Romans retreated, although Romulus soon changed his mind and turned around and engaged again.
Tullus on Expanding Rome
Tullus defeated the Albans, razed their city of Alba Longa, and brutally punished their traitorous leader, Mettius Fufetius. He welcomed the Albans into Rome, thereby doubling the population of Rome. Tullus added Alban nobles to the Senate of Rome and built the Curia Hostilia for them, according to Livy. He also used the Alban nobles to increase his cavalry force.
Tullus, who is described as more militaristic than Romulus, went to war against Alba, Fidenae, and the Veientines. He tried treating the Albans as allies, but when their leader acted treacherously, he conquered and absorbed them. After beating the people of Fidenae, he defeated their allies, the Veientines, in a bloody battle at the Anio River. He also defeated the Sabines at Silva Malitiosa by throwing them into confusion using his Albans-enhanced cavalry.
Jupiter Strikes Down Tullus
Tullus had not paid much attention to the religious rites. When a plague struck, the people of Rome believed it to be divine punishment. Tullus didn't worry about it until he, too, became ill and unsuccessfully tried to follow the prescribed rites. It was believed that Jupiter in response to this lack of proper reverence, struck Tullus down with a bolt of lightning. Tullus had reigned for 32 years.
Virgil on Tullus
"He shall found Rome anew-from mean estate
In lowly Cures led to mightier sway.
But after him arises one whose reign
Shall wake the land from slumber: Tullus then
Shall stir slack chiefs to battle, rallying
His hosts which had forgot what triumphs be.
Him boastful Ancus follows hard upon"
- Aeneid Book 6 Ch. 31
Tacitus on Tullus
"Romulus governed us as he pleased; then Numa united our people by religious ties and a constitution of divine origin, to which some additions were made by Tullus and Ancus. But Servius Tullius was our chief legislator to whose laws even kings were to be subject."
- Tacitus Bk 3 Ch. 26