From TA 1432 – 1448, Gondor was embroiled in a great civil war, resulting from the belief of some of the Dúnedain that Eldacar was unfit as a ruler because he was not of pure Dúnadan blood. Additionally, Eldacar’s father, Valacar, seemed to show more favour to the Northmen than to members of the royal family, this causing extreme discontent among many of the Dúnedain.
In 1432, a rebellion broke out in South Gondor; the rebels besieged Eldacar in Osgiliath, and in 1437 the king was forced to flee to his mother’s kin in Rhovanion. Osgiliath was burned and the palantír was lost, and Eldacar’s son, Ormendil, was captured and put to death by the most powerful of the rebels, Castamir, who was then made king.
As a king, Castamir was cruel and favoured only Gondor’s navy, thus arousing strong dislike of him in more inland areas of Gondor. In 1447, Eldacar returned from exile with an army of Northmen; and with much support from the Men of Calenardhon, Ithilien, and Anórien, he slew Castamir in the Battle of the Crossings of Erui. The remaining rebels were besieged in Pelargir, and sailed to Umbar in 1448, where they degenerated into Corsairs, troubling Gondor’s coasts for many generations.
Eldacar brought many of the Northmen to Gondor to help repopulate the devastated areas of his kingdom. Eldacar lived to be 235 years old, and in 1490 was succeeded by his second son, Aldamir.