Iridonia is the homeworld of the Zabraks. Due to the harsh living conditions, the Zabraks are a hardy species, taking to flight and space travel as soon as they could develop the technology; by the time the Duros encountered them, they had already colonized five systems.
As a Mid Rim world situated near important hyperspace lanes, Iridonia was one of the key worlds that connected the Outer Rim Territories to the Inner Rim. Situated where it was, it was often one of the first planets to be pulled into major conflicts and during the Old Sith Wars the planet was the site of numerous battles.
The First Battle of Iridonia - fought during the Great Sith War - was a major victory for the Galactic Republic and a turning point in the war which gave both the Republic military and the Jedi Order momentum which would help them to eventually defeat their Sith adversaries. The planet is officially allied with the Republic, although many Zabrak do not follow suit.