Popeye and Bluto were originally side characters

E. C. Segar’s comic strip Thimble Theatre was mainly focused around Olive Oyl and her boyfriend, Ham Gravy (original called Harold Hamgravy). Popeye and Bluto were introduced as side characters. Ham Gravy was later dropped and the three became staple on the animated series.

Popeye was introduced on 17^th January 1929, while the comic strip first appeared on 19^th December 1919.