Aleran was the Count of Barcelona from 848 to 852. He was also Count of Ampurias and Roussillon and Margrave

Margrave

A margrave or margravine was a medieval hereditary nobleman with military responsibilities in a border province of a kingdom. Border provinces usually had more exposure to military incursions from the outside, compared to interior provinces, and thus a margrave usually had larger and more active...

 of Septimania

Septimania

Septimania was the western region of the Roman province of Gallia Narbonensis that passed under the control of the Visigoths in 462, when Septimania was ceded to their king, Theodoric II. Under the Visigoths it was known as simply Gallia or Narbonensis. It corresponded roughly with the modern...

 together with Isembart

Isembart

Isembart or Isembard was the count of Barcelona, Empúries, and Roussillon and margrave of Septimania together with Aleran from 849 or 850 to 852.He was the son of Garí of Burgundy, count of Autun.He was named at the assembly of Narbonne in 849...

 from 849 or 850 to 852.

He was a Frankish nobleman loyal to the Emperor. At the Assembly of Narbonne

Narbonne

Narbonne is a commune in southern France in the Languedoc-Roussillon region. It lies from Paris in the Aude department, of which it is a sub-prefecture. Once a prosperous port, it is now located about from the shores of the Mediterranean Sea...

 in 849 he and Isembart were empowered to consolidate the territory for the Empire

Holy Roman Empire

The Holy Roman Empire was a realm that existed from 962 to 1806 in Central Europe.It was ruled by the Holy Roman Emperor. Its character changed during the Middle Ages and the Early Modern period, when the power of the emperor gradually weakened in favour of the princes...

 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

Bernat of Septimania

Bernard of Septimania , son of William of Gellone, was the Frankish Duke of Septimania and Count of Barcelona from 826 to 832 and again from 835 to his execution. He was also count of Carcassonne from 837. He was appointed to succeed his fellow Frank Rampon...

 eventually capturing the County of Barcelona in 850.