The illustrious son and heir of StewardCirion of Gondor, who first ruled in Minas Tirith while his father still lived, during the time of the war with the Balchoth. Cirion went to fight in that war, and left Hallas in command of the City of Gondor. In that war, too, Eorl brought his Northmen to the aid of Gondor, and after Gondor's enemies were defeated, Cirion gifted him the green land of Calenardhon as a reward. 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. It was Hallas, indeed, who renamed Calenardhon as Rohan, and gave its new people the name Rohirrim, Horse-lords.
Little is recorded of Hallas after he succeeded his father as Steward. He ruled Gondor in the time when Rohan was establishing itself - the Golden Hall of Meduseld was completed in the second year of his rule. At the great feast to celebrate the raising of the Hall, KingBrego's son Baldor made his rash promise to enter the Paths of the Dead, which led to his loss in the mountains. It is even possible that Hallas was present in person at that feast, though no record exists to prove this.
Hallas ruled Gondor for thirty-eight years, and was succeeded by his son, who became StewardHúrin II.
Notes
1
The date of Hallas' birth appears only in The History of Middle-earth volume XII, The Peoples of Middle-earth. It cannot therefore be considered completely reliable.
2
Sindarinhall- meant 'high' or 'exalted', and that is almost sure to be the primary element of Hallas' name. The final -as is less clear, though that form was often used as a noun-forming suffix, so the simplest interpretation of the name Hallas would simply be 'highness'.