In the Third Age, when the Northmen of Rhovanian were destroyed by the Wainriders of the East, a great part of the survivors of the war were gathered by Marhwini and settled in the Vales of the Anduin, between the Carrock and the Gladden Fields. Many fugitives from the North joined them. This was the beginning of the �oth�od, 'the Horse-people'. The Wainriders were defeated in an alliance of Gondor and the Northmen under leadership of Marhwini. But Marhwini was obliged to turn back to the Vales of the Anduin. In later days the �oth�od moved further north, to the lands between the rivers Greyling and Langwell. When Gondor was reigned by Cirion, the twelth Ruling Steward, it was threatened by Orcs and wild men from the Northeast. Cirion desperately requested Eorl, Lord of the �oth�od, for his help. Eorl came at once and the Orcs were driven back. As reward for their aid and the Oath of Eorl, concerning the alliance between the two peoples, Cirion gave the �oth�od, in TA 2510 all the great land of Calenardhon from Anduin to Isen. They called it the Mark of the Riders and themselves Eorlingas, but in Gondor they were known as the Rohirrim of Rohan. In the year 2758 Rohan was attacked by a great invasion from the East and the Dunlendings under the traitor Wulf. The Rohirrim were defeated, their land was overrun and many fled to Dunharrow. The winter of TA 2758-59 was very cold and both the Rohirrim and their foes suffered from it. But in Spring the ice melted and there were floods. The Easterlings disappeared, Wulf was slain and the Dunlendings were driven out with the help of Gondor. As the King and his heirs had all died by cold or sword, Fr�al�f, nephew of the King, became the first King of the Second Line. It was at this time Saruman appeared and took up his abode in Isengard. There after some time he drew Men and other creatures who hated both Rohan and Gondor.

Saruman behaved in the beginning like a friend, but in the year TA 3014 he attacked Rohan. There were the battles at the Fords of the Isen. The Eorlingas lost both and they suffered heavy casualties. Th�odred, heir to the throne, and Erkenbrand were killed. King Th�oden, who took advice from Wormtongue, a secret servant of Saruman, became despaired. It was not untill Gandalf healed him, before he undertook any action by himself against the formely White wizard. In TA 3019 the forces of Saruman were defeated at the battle of the Hornburg. In the same year the Riders set for Gondor to attack the army of the Witch-king. There on the Pelennor the forces of Sauron were destroyed and the both armies of Rohan and Gondor set for Mordor. They were almost defeated, but when the One ring was destroyed the tide turned, and were victorious. In the time that followed the Oath of Eorl was fulfilled and together with King Elessar they fought in wars that followed. Though Sauron was defeated his evil works still threatend both Kingdoms. And they did not rest till the White Tree could live in peace.