With the growth of the threat from Philistine incursions, the Israelite tribes decided to form a strong centralised monarchy to meet the challenge, and the Tribe of Reuben joined the new kingdom with Saul as the first king. After the death of Saul, all the tribes other than Judah remained loyal to the House of Saul, but after the death of Ish-bosheth, Saul's son and successor to the throne of Israel, the Tribe of Reuben joined the other northern Israelite tribes in making David, who was then the king of Judah, king of a re-united Kingdom of Israel.