Upon his father's retirement to a monastery in 945, their cousin Bernard, Count of Périgord took over the county on his behalf.
In 975, despite his illegitimate birth, Arnald laid claim to Angoulême and received the support of Duke William IV of Aquitaine.
[1] In the following years, Arnald consolidated and expanded his power at the expense of Bishop Hugh of Angoulême.
[2] Arnald supported William IV of Aquitaine in his feud against of Boso I of La Marche and captured his son Gauzbert, whom he handed over to the Duke.
[3] Arnald was married successively to Raingarde and Aldearde, the former of whom was the mother of his son William II.