Fleeing Dol Guldur in the Third Age, Sauron lived in Rhn for 400 years and gained many Easterling followers, as denoted in The Peoples of Middle-earth, the final History of Middle-earth book.

To understand Middle-earth's landscape in the First Age necessitates a brief history lesson. The Elves first awoke in Middle-earth, born fresh from their creator's Flame Imperishable in Cuiviénen.