Who were the philistines?

The true origin of the Philistines is not known. There is one fact that is without question, the Philistines were, are and will be the enemies of God. We do know they occupied the territory southwest of Israel between the Mediterranean Sea and the Jordan River. They were also know for using iron which was superior in battle against the bronze that the Israelites used. https://www.gotquestions.org/Philistines.html

Their god Dagon, is mentioned several times in the Bible; Judges 16:23-24, I Samuel 5 and I Chronicles 10:10. The Philistines relied on Dagon to give them victory in war. This is what made the confrontation with Goliath so distasteful to David. Goliath was basically saying that his god, Dagon, was more powerful than the God of Israel. He had been declaring for forty days the fact that his god was going to give him the victory. He was announcing that his god favored him over anybody that would accept his challenge.

The recent discovery of a Philistine cemetery may reveal more about their past.

There are several battles mentioned in the Bible between the Israelites and the Philistines.