Throughout his episcopate, he greatly expanded the authority of his diocese, making it the most powerful institution in Liguria and Sardinia, and notably increased its landholdings.
Pope Innocent II named Baldwin a cardinal-priest of Santa Maria in Trastevere no later than in 1137, when he appears for the first time in this dignity.
[2] In a letter of 22 April 1138, Innocent conferred on Baldwin the apostolic legateship over Porto Torres, Populonia, Galtelli, and Civita on Sardinia.
On 19 July 1139, at the exhortation of Bernard of Clairvaux and Otto of Freising, the emperor-elect Conrad III bestowed on him the countship of Pisa, making him the chief secular as well as ecclesiastical authority in the city and its countryside (contado, "county").
Bernard of Clairvaux even weighed into island politics and sent a letter to Pope Eugene III justifying Baldwin's actions.