In the Hebrew scriptures, the eldest son of King Saul and friend of David. A warrior in the Israelite army, he is first mentioned as victor over the Philistines at Geba. After David joined Saul's household, he and Jonathan became close friends. Saul became jealous of David's popularity and sought to kill him, but Jonathan prevented him. When the two met for the last time, they planned that David would be the next king of Israel and Jonathan his prime minister, but Saul and Jonathan were killed in battle at Mount Gilboa.