He was "pious and submissive to the church" and his extensive "donations of privileges and judicial lands impoverished his state of glory.
They desired to maintain a condominium in Arborea, but internal fighting allowed Peter to solidify his authority with little opposition.
In 1231, Eldiarda, Peter's regent in Bas (Spain), tried to pass the viscounty to her son Simon I of Palau, who married Güeraua d'Anglesola.
In 1241, Peter and James I of Aragon finally recognised this new viscount.
In 1222, he married Diana Visconti, sister of Lambert of Gallura, at the insistence of Ubaldo.