Page 99 - The Early Republic

When Tarquinius had been driven out, two consuls began to be appoint-
ed for one king in order that, if one was bad the other would stop
him. They were assigned to rule for one year, in order they might not
become more arrogant through the long duration of power. Therefore
the consuls in the first year, after the king had been expelled were
L. Iunius Brutus, the fierce protector of liberty, and Tarquinius
Collatinus, the husband of Lucretia. But Tarquinius was asked to
leave. It was resolved that all of his family should move from the
city, and in this place Valerius Publicola he was made consul.

King Tarquinius stirred up a war with the city. In the first battle
consul Brutus and Arruns, Tarquinius' son, they kill each other.