After the conquest of the land by Joshua until the formation of the first Kingdom of Israel in c. 1050 BC, the Tribe of Gad was a part of a loose confederation of Israelite tribes. No central government existed, and in times of crisis the people were led by ad hoc leaders known as Judges (see the Book of Judges). 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 Gad 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 Saul's son Ish-bosheth, successor to the throne of Israel, the Tribe of Gad joined the other northern Israelite tribes in making Judah's king David the king of a re-united Kingdom of Israel. However, on the accession of David's grandson Rehoboam, in c. 930 BC the northern tribes split from the House of David and from Saul's tribe Benjamin to reform Israel as the Northern Kingdom. Gad was a member of the Northern Kingdom until the kingdom was conquered by Assyria in c. 723 BC and the population deported.