Hercula was a class M planet located in the galaxy's Alpha or Beta Quadrant. It was the homeworld of the indigenous Yerba cavemen and the colonial Herculese civilization.
Hercula had at least two lush continents along with vast oceans. Terrain included forests, valleys, hills and mountains.
In the 7700s B.C., Herculese landed colonial transports on Hercula and established a permanent colony. Native, primitive Yerba were quickly subjugated.
In 2266, a distress call for help against wild animal attacks brought the Federation starship USS Enterprise to Hercula. James T. Kirk, Spock, Leonard McCoy and Montgomery Scott were present as increasing Yerba attacks led to a brief planetary civil war ending with the emancipation of the Yerba.
A statue of martyrs Germal and Jivi was erected at the highest point on the surface as a monument to peace. Governorship of the planet was to be shared equally. (TOS comic: "The Animal People")
In 2269, Colonel James Briton updated Kirk on the status of Hercula, mentioning that the two races were integrating but not yet truly equal. (TOS comic: "The Enterprise Logs, Volume 4")