Sometime in the early thirteenth century, Gondor began to sense that the Easterlings were once again becoming a threat as they were apparently conducting raids on the Northmen of Rhovanion. Needing allies, Gondor granted them lands south of Greenwood the Great hoping they would stand against the Easterlings in support of Gondor, so there were no major open battles between Gondor and the Easterlings at this time.
The attacks began again during Narmacil's time and were at first not very large and not enough for Gondor to respond directly in open battle. The situation changes a short time afterwards when word reached Minalcar, the Regent of Gondor that some of their Northman allies were unreliable and agreed to fight on the side of the Easterlings out of promises of a share in the spoils of war, greed, or out of the need of allies to aid in the settling of feuds between their princes. This prompted Minalcar to take action directly against the Easterling invaders.
In TA 1248, Minalcar led a great army out of Gondor and met a large Easterling army somewhere between Rhovanion and the Sea of Rhûn. Here, Minalcar utterly defeated them on the field of battle and proceeded to destroy all their encampments east of the Sea of Rhûn, threatening both the realm of Rhovanion and Gondor.
After the war, Minalcar renamed himself 'Rómendacil' increasing his popularity within the realm. He fortified the west shores of the Anduin and built the Argonath both as defenses and warnings to all possible invaders of Gondor. The Northmen of Rhovanion was also brought under full influence of Gondor.