Odo was the second Count of Fézensac from 960 to his death.

Odo was the eldest son and successor of William Garcés

William Garcés of Fézensac

William García was a Count of Fézensac. He was the second son of García II of Gascony and Amuna....

. Odo's younger brother Bernard

Bernard I of Armagnac

Bernard I , called the Suspicious, was the first Count of Armagnac.He was the second son of William Garcés of Fézensac. When William died in 960, he divided his county up, giving Fézensac to his eldest son Odo, Armagnac to Bernard, and Gause to the youngest son Fredelon.For his many sins, Bernard...

 received Armagnac

Armagnac (region)

The hilly countship of Armagnac , in the foothills of the Pyrenées between the Adour and Garonne rivers, is a historic countship of the Duchy of Gascony, established in 601 in Aquitaine...

 in a partition of their father's territory.

Odo spent his first years pillaging neighbouring lands and committing a number infractions against the Church

Roman Catholic Church

The Catholic Church, also known as the Roman Catholic Church, is the world's largest Christian church, with over a billion members. Led by the Pope, it defines its mission as spreading the gospel of Jesus Christ, administering the sacraments and exercising charity...

. For this he was nicknamed Falta or the Fool by ecclesiastical chroniclers. In his later life he made amends by donating the church of Saint-Martin de Berdale to the canons of Saint-Marie.

He was succeeded by his only son, Bernard.