- The alliance between Rohan and Gondor came into existence in TA 2510. In that year a new group of Easterlings known as the Balchoth launched a massive invasion of Gondor.
- The army of Gondor was defeated and trapped between the Limlight and the Celebrant. Gondor, which had always been on friendly terms with the different tribes of the Northmen, sent messengers to the closest tribe, the Éothéod. Although it was unlikely that the message calling for aid would come through, it did. Then Eorl the Young and his fierce Éothéod Riders unexpectedly took the field during the Battle of the Field of Celebrant and turned the tide in the favour of Gondor.
- As a reward Cirion, the Steward of Gondor, gave Eorl the depopulated province of Calenardhon for his people to settle, while fulfilling Gondor's need for a strong ally.
- The Oath of Eorl was sworn by both Cirion and Eorl and neither nation has broken the alliance ever since.
- Celebrían, daughter of Galadriel and Celeborn weary of the world after her torment by the orcs departs Middle-earth to the Undying Lands.