Oath of Eorl
From the One Wiki to Rule Them All, the Lord of the Rings Encyclopedia.
Cirion took Eorl, Lord of the Éothéod to the hallowed site of Amon Anwar and there before the Tomb of Elendil they swore what would be in later days known as the Oath of Eorl, giving Calenardhon to the Éothéod, and promising eternal friendship between the two Kingdoms. As Amon Anwar was no longer the centre of Gondor, rather its border, Cirion removed the Casket that Isildur had set upon the hill two thousand years earlier to Rath Dínen, the Silent Street, where all other Kings of Gondor were entombed.
