Cirion was born in the middle earth of Tolkien in 2449 year of the third age. In 2489, Cirion became a steward of Gondor.
After that, the people of Rhun attacked Gondor. Cirion asked the people of Eotheod for help. But since there was no help, Cirion began fighting the Rhun army. Cirion has lost this war. And at that time Orcs started attacking too Gondor. The Rhun and Orc armies have surrounded Cirion and his army. Exactly in the meantime, Young Eorl emerged. Together with the army of Eorl defeated both Orclar and Rhun army.
After the war, Cirion gave lands to Eorl as a gift. And in this land the kingdom of Rohan was established. Cirion died in the 2567 year of the third age.