Both Narmacil I and Calmacil were seen as idle kings, enjoying luxury rather than fortifying the borders of Gondor. Minalcar was not that way inclined, to further strengthen Gondors power he began recruiting Northmen into his service.
As Regent he was seen as ruthless and vigorous, squashing Easterling attacks on the border and defeating an army of Easterlings between Rhovanion and the Sea of Rhun.
After this battle he took the name Romendacil.
Also after the victory he fortified the Western side of the River Anduin up to Limlight.