On star wars, Polis Massa is a cluster of asteroid. It's well known to be the birth place of Luke and Leia Skywalker.
Its inhabitants where digging searching for trace of then ancestors. Their base had a medical facility and the Polis Massans were good healers. During their investigations, a few Polis Massans rose to power in a dictatorial fashon some time before 200 ABY, changing the Polis Massans obejctives from archaology to mining precious crystals.
The planet was eventualy conquered by Malachor V, in an attempt by the Underlord to free to people of Polis Massa and usher in an era of Republic-style government. The Polis Massans were free of their previous dictators, but as the current Republic crumbled, they simply traded one master for another, as the Underlord continued to control the planet far after the demise of their previous leaders.
Polis Massa on wookiepedia.