Conversation so far:
When was the Second Punic War?
221 BC.
Who won the war?
Rome invaded and conquered Lusitania and Celtiberia.
What kind of weapons were used?
CANNOTANSWER.
What groups of people fought against each other?
many Iberian and Celtiberian warriors fought for both Rome and Carthage.
Are there any well known warriors?
CANNOTANSWER.
Are there any other interesting aspects about this article?
Wars and campaigns in the northern regions of the Iberian peninsula would continue until 16 BC, when the final rebellions of the Cantabrian Wars were defeated.

Question: What started the war?
Self-contained rewrite: What started the Second Punic War of 221 BC?