Nearly four centuries later Giorgio Vasari wrote: "Guglielmo, according to what is being said, in year 1174 with Bonanno as sculptor, laid the foundations of the bell tower of the cathedral in Pisa."
Gati kater shekuj me vone Xhorxho Vasari shkroi : “Gulielmo, duke u bazuar mbi atë çka thuhet, ne vitin 1174, bashke me Bonanon si skulptor, vuri themelet e kullës se kembanes se katedrales ne Piza.