 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 Manasseh 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 succeeding son Ish-bosheth to the throne of Israel, the Tribe of Manasseh 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.