The Corsairs of Umbar were chief among the foes of Gondor in the later Third Age. They were brigands, pirates and seaborne raiders.

The enemity of the Corsairs towards Gondor was long-standing, partly due to the determination of the Kings of Gondor to allow no enemy or independent lordship within striking distance of their might.

Umbar was situated in the south, along the coasts of the Harad. In TA 1447, Umbar fell from Gondor's control when the sons of Castamir and the remaining rebel fleets of Gondor seized the Haven as a refuge. The Corsairs, as they were then known, raided Gondor's coasts ceaselessly until TA 1810 when Telumehtar re-took the port and killed the last of Castamir's line.

The Corsairs continued to harry Gondor's coasts through the rest of the Third Age, though not at the level of their previous activity. The last that is known of the Corsairs is from TA 3019, the date that Aragorn captured their fleet and sailed it to the aid of Minas Tirith. This was not their first defeat at Aragorn's hands. Nearly forty years earlier, in his guise of Thorongil, he led a devastating Gondorian attack on Umbar that left the Corsairs' fleets all but destroyed.
Encyclopedia entry originally written by atalante_star