Nino Visconti of Gallura having been deposed in 1288, John was the only judge and Arborea the only giudicato left on the island of Sardinia.
Nino Visconti Gallura digulingkan pada tahun 1288, John merupakan Giudice Arborea satu-satunya dan giudicato satu-satunya yang tinggal di pulau Sardinia.