"Blondie" was adapted into a long-running series of 28 low-budget theatrical B-features, produced by Columbia Pictures. Beginning with "Blondie" in 1938, the series lasted 12 years, through "Beware of Blondie" (1950). The two major roles were Penny Singleton as Blondie and Arthur Lake (whose first starring role was another comic strip character, Harold Teen) as Dagwood. Faithfulness to the comic strip was a major concern of the creators of the series. Little touches were added that were iconic to the strip, like the appearance of Dagwood's famous sandwiches—and the running gag of Dagwood colliding with the mailman amid a flurry of letters, which preceded the title sequence in almost every film.