One of the earlier kings of Rome was Tullus Hostilius. He became king in 673 after the death of Numa Pompilius and was one of the more war-focused rulers. The most important of his wars was against Alba. The people of both their towns had been stealing from the other, in petty theft. So Tullus wanted to go to war against them. The general from Alba was named Mettius and said since they were guilty of the same crime and if they did go to war they would be greatly weakened he suggested that they have their champions fight. Their champions were a set of triplets from each side for Rome there were the Horatii Brothers and from Alba, there were the Curratii brothers.
The two sets of brothers set up the duel and fought. Only one survived and he was one of the Horatii brothers from Rome. In the fight three of the Curatii brothers were wounded on not so hurt and the others both hurt while two of the Huratii brothers had been killed and one was unscathed. The last one from Rome killed two to avenge his brothers and killed the last for Rome.
So Rome won, and Alba had to come and help whenever they needed it. But Mettius thought he could have won and didn’t want to fully admit to Tullus. And when Rome did call on them they just sat on the sidelines. Rome did win the battle and after, he went to the Alban army and gave a speech. He said that they should have come to his aid but that the army is only as good as their leader. So Tullus took Mettius and attached each of his limbs to four horse-drawn chariots and started them all of ripping him apart.
Tullus added the population to Alba to Rome greatly increasing their power. But he died suddenly in 642 BC before he was going to fight the Sabines. He was struck with a disease but died from lightning striking his house and burning to the ground. Some of the people said that Zeus was angry with him for not worshiping him properly. So what was a freak act of nature was attributed to the “power” of the gods, so then the people began to worship and fear Jupiter more than the other gods.