The Secret 4 pressbook is the oldest one I have, so far, for a movie serial. Unfortunately, like many silent-era movies, this one is considered lost as no copy of the film has surfaced. There were 15 chapters of thrilling action, headed by Eddie Polo, who came from a circus family. He had trained in multiple acrobatic disciplines and toured with various circuses. His background, naturally, led to him becoming a stuntman for Universal in 1913. Stardom kicked in early due to his action-oriented appeal. He was the first man to parachute off the Eiffel Tower (IMDb). As his stardom waned with age and the advent of sound, he made due as a makeup artist and trying to get his life story onto film.
Kathleen Myers appeared in 22 movies and played the leading lady in a number of adventure productions (Wikipedia). Perhaps her most remembered role was in Go West with Buster Keaton. She also appeared a few times alongside Oliver Hardy before he teamed up with Stan Laurel.
