Lord Charles (1976)

“In the parlance of big league dugouts, there are no curve balls, only ‘breaking ball’ for the smallish variety and ‘Uncle Charlies’ for the large, made-in-Hades variety. The hitters of the American League have decided that the curve that Bert Blyleven throws deserves more than the humble name ‘Uncle Charlie,’ as in ‘Hey, Bert. How’s your Uncle Charlie?’ Blyleven’s overhand curve, the best in baseball today, has been christened The Lord Charles, as in ‘How’d you guys do when you met up with The Lord Charles?’” Thomas Boswell, Washington Post, June 15, 1976, pD1

No earliest use given in 2009 Dickson Baseball Dictionary