War of Wrath
Ossiriand ("Land of Seven Rivers") was the most easterly region of Beleriand during the First Age, between the Ered Luin and the river Gelion. The Seven Rivers were the Gelion which ran from north to south, and its six tributaries flowing from the Ered Luin, named (from north to south) the Ascar, the Thalos, the Legolin, the Brilthor, the Duilwen, and Adurant. Ossiriand was a green and forested land. It was the only part of Beleriand that survived the War of Wrath, becoming known as Lindon, where Gil-galad and Círdan ruled.