He was a Frankish nobleman loyal to the Emperor. At the Assembly of Narbonne in 849 he and Isembart were empowered to consolidate the territory for the Empire and bring the Hispanic Marches held by rebel forces loyal to Pepin II back into control of the empire.
Aleran and Isembart campaigned against William, son of Bernat of Septimania eventually capturing the County of Barcelona in 850. Thereafter they ruled the Counties jointly. Aleran died sometime in 851 or 852 and Isembart continued to rule alone until the Emperor appointed Odalric to Count of Barcelona in 852.
