The Stewarts greatly increased their holdings in the west, in Atholl, and in the far north: the earldoms of Fife and Menteith went to Robert II's second surviving son, Robert; the earldoms of Buchan and Ross (along with the lordship of Badenoch) to his fourth son, Alexander; and the earldoms of Strathearn and Caithness to the eldest son of his second marriage, David. King Robert's sons-in-law were John MacDonald, Lord of the Isles, John Dunbar, Earl of Moray and James who would become the 2nd Earl of Douglas. Robert's sons John, Earl of Carrick, the king's heir, and Robert, Earl of Fife, were made keepers of the castles of Edinburgh and Stirling respectively, while Alexander, Lord of Badenoch and Ross, and afterwards Earl of Buchan, became the king's Justiciar and lieutenant in the north of the Kingdom. This build-up of the Stewart family power did not appear to cause resentment among the senior magnates—the king generally did not threaten their territories or local rule and where titles were transferred to his sons the individuals affected were usually very well rewarded. This style of kingship was very different from his predecessor's—David tried to dominate his nobles whereas Robert's strategy was to delegate authority to his powerful sons and earls and this generally worked for the first decade of his reign. Robert II was to have influence over eight of the fifteen earldoms either through his sons directly or by strategic marriages of his daughters to powerful lords.