There are many progenitors who are significant contributors to the super-hero genre, but I would argue that the one predecessor who incorporated most of the elements of the super-hero genre in one place and created something that could be recognized as a "super-hero" once the term came into usage later was Lee Falk's Phantom which featured the following-

-costumed hero with mask, cowl and underwear on the outside of a skin tight spandex type suit
-secret identity and soubriquet-The Phantom was Kit Walker, also called the Ghost Who Walks
-recognizable symbol as part of the costume (the skull rings and skull belt buckle)
-secret origin and legacy
-a hidden lair to use as a base of operation (the Skull Cave)
-sidekicks and assistants-his horse and wolf
-contacts in the local law enforcement agency-the Bangalia Jungle Patrol-who would provide information and help on cases
-activities focused on crime-fighting of various sorts (though in a jungle not urban setting)
-arch enemies (such as the Singh Brotherhood)

yet all of this was in 1936 before super-hero comics debuted with Superman in Action Comics. Several of the others mentioned here were vitally important as progenitors of the super-hero genre, but none of them had as many elements that would become di rigeur in super-hero comics synthesized and coalesced in one place as the Phantom strip did. And it was a syndicated strip reaching millions paving the way for audience acceptance of all those elements working together as normal for other characters who would adopt them. However it was later than some of the others and may not have been as big an influence on Sigel and Shuster as some of the others, but it sure was influential on the audiences who would encounter super-hero comics and whose acceptance of those genre tropes were critical to the success of the genre when it did appear.

-M