De Blasio wasn’t officially “Bill de Blasio” until January 2002. He had two other names prior to that. Born Warren Wilhelm Jr., he changed his name for the the first time in 1983 — to Warren de Blasio-Wilhelm — to embrace his mother’s Italian heritage, he wrote in his petition to the court. By 1990, he was using the name Bill de Blasio, which became official when a judge approved his application for a second name change in January 2002