In addition, Giles worked vigorously to keep premier players in his league. After the advent of interleague trading without waivers in November 1959, he lobbied against the trade of National League superstars to the American League to preserve the NL's hegemony. He was successful until his former team, the Reds, traded Frank Robinson to the Baltimore Orioles after the 1965 season. Under Giles, the National League began a 33-year (1956–1988) streak during which it dominated the American League in attendance—a remarkable achievement, given that the Junior Circuit had two more member teams than the NL during 13 of those seasons (in 1961 and 1977–1988).