Tullus Hostilius was chosen by the senators because he was a Roman and because his grandfather had fought with Romulus against the Sabines. After the death of Numa Pompilius the spirit of peace seemed to weaken. Friendly feelings between the Romans and the contrymen of Alba Longa in the hills outside of Rome gave way to quarreling because people began to raid each others fields and gardens, stealing each other's crops and animals.
When the ruler of the Albans complained to Tullus Hostilius, he, like a small boy said, "You started it!" The Alban and Roman armies prepared to fight. The Romans defeated the Albans and they were subjects of the Roman state. When they refused to help Rome in a battle, Hostilius had their leader torn in two by chariots running in opposite directions. He had Alba Longa destroyed and gave the Albans the Caelian Hill to live on.
Tullus Hostilius was a warring king. He engaged in another war with the Sabines[?].
Legend has it that Tullus was so busy with one war after another that he neglected any service to the gods. A dreadful plague came upon the Romans. Even Tullus was stricken with it. He begged Jupiter for his favour and help. The god's answer was a bolt of lightning which shot down from heaven to burn up the king and his house to ashes.
This was seen as an omen to the Romans that they had better choose a new king who would follow the peaceful example of Numa Pompilius. They chose Ancus Marcius, the grandson of Numa Pompilius.