He took the crown in 1149 of the Third Age after the death of his father Hyarmendacil. His father had secured Gondor with it being at its height of power and influence. In line with his love of luxurious items Alcarian replaced the Crown of Gondor with a jewelled helm, similar to those of the Citadel Guards (pictured above).
A ruler that could be argued as lazy, as during his reign he failed to further secure the power Gondor held and the watch of Mordor suffered because of it.
He was succeeded by his eldest son Narmacil I.