Very few all American-developed NHL players emerged in the 1950s and 1960s, Tommy Williams, was the only American citizen to play regularly. Both Williams and Mariucci complained about anti-American bias, and U.S. Olympic team stars John Mayasich and Bill Cleary turned down offers from NHL teams. Although there were several European-born players (e.g., Slovakian-born Hall of Famer Stan Mikita) who immigrated to Canada as children, the only European-born and trained player of the era was Sweden's Ulf Sterner, who briefly played for the Rangers in 1965. The league's first Black player, Willie O'Ree, came up during this era, playing for the Boston Bruins between 1958 and 1961, although he turned out to be the last Black player until the 1970s.