Hallas succeeded his father Cirion at his death in T.A. 2567. Calenardhon had been given by his father to the Éothéod, and this people began to migrate to the land. Hallas devised the names Rochand and Rochirrim for the land and its people, which became Rohan and Rohirrim in the Sindarin dialect of Gondor. In effect Gondor had been halved in size, but it had gained a strong ally to the north.
War never ceased on Gondor's eastern borders as the Balchoth were not completely destroyed, but they were no longer a serious threat. More a problem were the Corsairs of Umbar, who kept raiding the coasts.
He was followed by his son Húrin II at his death in 2605.
In some early variants of the Quenta Silmarillion tradition published in the History of Middle-earth series, Hallas is also the name of the son of Orodreth. He was replaced by Gil-galad, later High King of the Ñoldor, who in the published Silmarillion is made into Fingon's son instead. That Orodreth's son was named Hallas was an earlier idea, but Gil-galad replaced him. In the published Silmarillion, Orodreth has no son.
Cirion went to fight in that war, and left Hallas in command of the City of Gondor.
Hallas was a witness to the Oath of Cirion and Eorl, in which the two leaders stood beside the Tomb of Elendil and promised a bond of friendship between their two nations.
Hallas ruled Gondor for thirty-eight years, and was succeeded by his son, who became Steward Húrin II.
Hallas (Third Age 2480 – 2605, aged 125 years) was the illustrious son and heir of Steward Cirion of Gondor, who first ruled in Minas Tirith while his father still lived, during the time of the war with the Balchoth.
Hallas was a witness to the Oath of Cirion and Eorl, in which the two leaders stood beside the Tomb of Elendil and promised a bond of friendship between their two nations.
Hallas died in Third Age 2605 and was succeeded by his son, who became Steward Húrin II.