Comics historian Don Markstein traced the history of the characters in his Toonopedia: Mike & Ike started while Goldberg was in San Francisco, working as sports cartoonist for that city's Bulletin (where he'd replaced another great, Thomas A. "Tad" Dorgan, creator of Judge Rummy and his pals). The identical twin morons were originally done as a half-page Sunday series for World Color Printing Co., which later printed most of America's comic books. At the time, it was functioning as both a printer and a syndicate for Sunday comics, distributing Slim Jim, Major Ozone and several others. They didn't have much impact there, but the concept hung around. For years afterward, Goldberg often slipped Mike & Ike panels, in which they played straight man and gag man, onto the ends of his daily comics