When one of Gregory Gideon's oiling operations discovered the Serpent Crown, Gideon wore the artefact and was convinced by Set to bring together some of the world's most influential businessmen to help spread Set's influence across the planet.
The Serpent Cartel were created by Steve Englehart and George Perez and first appeared in The Avengers #144.
During Marvel's Atlantis Attacks crossover, the Serpent Cartel was fleshed out by writer and comic book historian Peter Sanderson who developed their entire back-story as well as their membership.
Major Story Arcs
Serpent Crown Saga
The Serpent Cartel use the Serpent Crown to influence the Squadron Supreme and send the heroes up against the Avengers.