The Galactic Empire seized control of the planet Wayland, an event known as the occupation of Wayland. During this period, Imperial engineers excavated the interior of Mount Tantiss. In response, the indigenous Myneyrshi and Psadans united, hoping to overthrow the occupying forces. The Myneyrshi soon realized their crossbows, despite their power, couldn't penetrate the Imperial battle armor. Ignoring the primitive weapons of the natives, the Emperor's engineers initiated the construction of an extensive network of chambers deep within the mountain, complete with a complex maze of internal defenses. The Empire enslaved the local population, forcing them to build this massive complex under Mount Tantiss. Once the project was finished, the engineers departed.
Instead of deploying a defensive battalion of AT-ATs that might attract attention, the Emperor assigned a Dark Jedi Guardian to protect Mount Tantiss and sealed the entrance. The Psadan later claimed that the Guardian tried to dominate the inhabitants of Wayland.
In the year 3 BBY, Imperial Research Station 61 was established on the planet. Colonel Milosh Muhrlein, the commandant in charge, began selling his staff's technological developments on the black market to fund his extravagant lifestyle. Imperial Intelligence Agent Jahan Cross discovered Muhrlein's illicit activities, prompting Muhrlein to attempt to bribe him into silence. Failing in this attempt, Muhrlein tried to kill Cross, but he failed and was killed himself.
The Imperial occupation of Wayland came to an end shortly after the Battle of Endor in 4 ABY.