[a] His reign was characterised by ceaseless wars and litigations with his more powerful cousin and neighbour Raymond IV of Pallars Jussà.
Artau was the second son of William II of Pallars Sobirà and his wife Stephanie, a daughter of Ermengol I of Urgell and Tetberga, who was related to either the Counts of Provence or Forez.
In relation to his military operations both defensive and offensive directed against the county of Pallars Jussà, Artau constructed several new castles: Montcortés, Peramea, Bresca, and Baén.
[4] A second agreement of this sort was reached on 30 May 1067: Artau ceded the monastery of Santa Maria de Lavaix and quitclaimed several villages (villae) to Raymond.
This time Raymond gave up the right to control (potestas) the castle of Talarn to two of his chief magnates, Pere Ramon I d'Erill and Mir Guirreta II de Bellera, while Artau granted the same of his castle of Salás to two of his men, Guillem Guitard de Vallferrera and Ramon Bernat.