Ronald James Padavona (July 10, 1942 – May 16, 2010), better known as Ronnie James Dio, was an American heavy metal vocalist and songwriter. He performed with, amongst others, Elf, Rainbow, Black Sabbath, Heaven & Hell, and his own band Dio. Other musical projects include the collective fundraiser Hear 'n Aid. He was widely hailed as one of the most powerful singers in heavy metal,renowned for his consistently powerful voice. He often ranks as one of the greatest rock vocalists of all time in various online polls and lists. He is credited with popularizing the "metal horns" hand gesture in metal culture. Dio died of stomach cancer on May 16, 2010.

Source:  http://en.wikipedia.org/wiki/Ronnie_James_Dio