How did a war begin between the Titans and Zeus?

Cronos, Zeus' father, was Titan. There was a prophecy that a son born to Cronos would overthrow him. So Cronos ate all of his kids. But his wife, Rhea, saved Zeus and had nymphs raise him.

Zeus grew up and Rhea brought him to the palace to be the wine bearer. Cronos was pleased. One day Zeus made a concoction that caused Cronos to vomit up the gods inside him, Zeus' siblings.

Cronos had also had the 100 Handed Ones and the Cyclops, which he sent into exile.

In the war, Zeus and his siblings along with the 100 Handed Ones and Cyclops and some of the other Titans, they fought against Cronos.

At the end, Cronos was sliced up and thrown into the pits of Tartarus.

This is not historical, since it is a Greek myth.