The Enslavement of Vulcan was one of the first enslavements carried out by the Galactic Empire. It was commanded by newly-promoted Grand Moff Willhuff Tarkin in 18 BBY.
With the end of the Clone Wars and the establishment of the Galactic Empire, construction on a superweapon, the Death Star, promptly began. It was designed to have enough firepower to destroy entire planets. However, numerous problems and difficulties plagued the construction. These included sabotage, labor shortages, engineering accidents, design problems, and supply difficulties. In order to try to speed up the project, Grand Moff Willhuff Tarkin, with the Emperor's approval, began a series of enslavement campaigns to bring slave labor, mineral resources, and scientific labatories under the control of the Empire. The Vulcans would be amongst the first targets, as would the Wookiees and Romulans. They had been respected members of the Old Republic since that government was established in 25,053 BBY. They also had great expertise in science, physics, engineering, and technology, which could be put to use in the design and engineering of the Death Star. Tarkin wanted to exploit this. So he launched the enslavement campaign against them.
A Imperial fleet of 46 Star Destroyers, under Tarkin's command, appeared in orbit over Vulcan. However, they promptly ran into a small defense fleet of 38 Vulcan defensive warships, which had been hastily constructed by the Vulcans to prevent Imperial conquest of their world. The Imperials quickly destroyed the defense fleet, although losing 3 Star Destroyers. Afterwards, Grand Moff Tarkin ordered the landing of stormtroopers and enslavement units to take care of what he believed to be the "defenseless population".
Transports deployed to the planet. Promptly, around 38 million stormtroopers were landed, as were 28,000 AT-AT walkers. However, they encountered resistance from groups of Vulcan militia, and had to fend these off. They eventually crushed them, but had lost 120,000 clone troops. After wiping out the last Vulcan ground defenses, the stormtroopers and enslavers moved swiftly across the planet. They enslaved Vulcans in all the deserts and dry countryside, and, then, finally, surrounded the Vulcan cities. After four days, the Vulcan High Command surrendered, thus bringing their planet under formal Imperial control.
In the wake of the High Command's surrender, the Empire swiftly moved in occupation forces. All of the Vulcans were enslaved, and more then 450,000 of them were moved into Imperial concentration camps around Mountain Selaya. Many would be shuttled off to the Maw Installation, forced to use their scientific and engineering skills in the construction of the station. Vulcan scientific academies and labatories also came into Imperial control. The Empire would use them for the research, development, and refinement of scientific research projects.
Across the Universe, many people were outraged at the Empire's actions against Vulcan, long respected by the universal community. The event pushed Senators Mon Mothma and Bail Organa even more in the direction of eventual rebellion.