The Ring is Lost

Isildur is killed and the Ring is Lost.  Gondor and Arnor are sundered.

Isildur and all his sons killed at Gladden Fields. Ring is lost. Gondor and Arnor sundered and Gondor begins to pursue a different course. Gondor expands under rule of Anarion's descendants while Arnor declines under line of Isildur over the next Millennium. Capital of Arnor shifts from Annuminas to Fornost Erain.