The planet was inhabited by a primitive tribal species, until a secret Imperial expedition of the Inquisitorius stumbled across it in 18 BBY. The Imperials first built a base and then a temple, one of the Inquisitorius' headquarters. The dark influence of the structure soon corrupted the entire world, much like Byss, so Emperor Palpatine could settle Bastion with Human colonists. By 12 BBY, the whole planet was covered by urban sprawl, interrupted by fortifications and the magnificent Temple of the Inquisitors.