One of his first acts was to order the giudici to punish the murderers of the bishop of Ploaghe, the abbot of Tregu, and the vicar of Camaldoli.
On 22 March, with papal consent, he gave Christian burial to Comita's father, Constantine II, who had died excommunicate.
In a letter dated that same day to Comita, William, and Hugh I of Arborea, the pope ordered the giudici to take an oath of allegiance to Biagio, thus breaking their link of fidelity to Pisa.
Then the three Sardinian archbishops – Biagio, Riccus of Cagliari, and Bernard of Arborea – excommunicated the giudici for trying to solve their problems in the saecular forum (i.e., through war).
However, Biagio's relationship with the papacy soon deteriorated and Innocent ordered him to confirm the marriage alliance between the houses of Bas (Arborea) and Massa (Cagliari).