Namesakes
Guglielmo Marconi
(m) 1874-1937 
Nobel Prize Winners 1909 (physics)
Notable Scientists and Inventors
Willie Pep
(a.k.a. Guglielmo) (m) 1922-2006
Notable Athletes (boxing)
William of Vercelli
(a.k.a. Guglielmo) (m) 1085-1142
Saints