Leonops was established by Mahes, an ashrak who was once in the service of Ra. After a falling out between Ra and Maat, Mahes was exiled was he was considered to possibly be loyal to Maat. No longer having access to his city on Earth—Leontopolis—Mahes took several of his loyal slaves and Jaffa to the then unnamed planet and established a small colony.
Over time, Mahes constructed several large arenas on the planet which would be used for ingenious trials. It was in these arenas that he placed a new form of healing technology, which had the ability to resurrect beings who entered the arenas over and over again for his amusement. Through these arenas, Mahes' planet was able to serve as a form of dispute settlement as well as amusement for other Goa'uld, bringing him back into the graces of Ra.
A few years after the destruction of the Ori, Leonops was visited by the Tau'ri of Stargate Command who were scouring the planet for Mahes' resurrection technology. Whilst on the planet, they accidentally entered into the Court of Judgment and triggered the games. They were shortly joined by forces from the System Lords Third Battle Group, both groups battling to the death repeatedly before the Tau'ri eventually won. Both sides left the planet shortly after, alive only due to Mahes' technology.