2948 TA

In the year 2948 of the Third Age in the Land of Rohan, Theoden son of Thengel, King of Rohan was born. 

Theoden became king of Rohan in the year 3980 and reigned until he was killed by the Witch King of Angmar on March 15^th 3019 TA. He was 71 years old at the time of his death. The story of his death and the battle for Minas Tirith is told in "The Battle of the Pelennor Fields" being chapter 6 of Book Five in The Lord of the Rings.

Theoden earned great renown in the Battle of The Hornburg on March 3rd and 4th 3018 TA when he and Aragorn son of Arathorn rode out into the midst of the enemy, with a small company of horsemen.

There also it is told how Eowyn and Meriadoc killed the Witch King and how Minas Tirith was saved.  

After Theoden died, his nephew, Eomer son of Eomund becomes King of Rohan.