Guglielmo Marconi | Guglielmo Oberdan | Guglielmo Cavallo | Ferrante Pallavicino | Carlo Pallavicino | Guglielmo Vaccaro | Guglielmo Tocco | Guglielmo Ratcliff | Guglielmo Plüschow | Guglielmo Picchi | Guglielmo Massaia | Guglielmo Libri Carucci dalla Sommaja | Guglielmo Achille Cavellini |
He was the second son of the Marquis Guglielmo Pallavicino (also known as Pelavicino), a descendant of the Obertenghi of Liguria, who ruled over a series of fiefs in the area between Parma and Piacenza which were known collectively as the Pallavicino State.
A number of lines descended from Guglielmo (died 1217), possessor of a series of fiefs between Parma and Piacenza and a descendant of the Lombard Obertenga family (along with the Este, the Cavalcabò and Malaspina).