The Mission to Endor was undertaken immediately after the Battle of Hoth in order to find a suitable site for the Second Death Star's shield generator.
Imperial General Brenn Tantor commanded a light scouting force that landed on the Forest Moon of Endor. His mission was to reconnaissance three separate sites that were under consideration to serve as the location of the shield generator that would be used to protect the Death Star.
Almost immediately after landing, Tantor's forces were attacked by the natives. Reluctant to engage until he could determine if they were genuinely hostile or merely civilians defending their territory, Tantor was countermanded by his superior, Grand General Malcor Brashin. Brashin ordered him to eliminate all natives that offered resistance and sent down reinforcements for that purpose.
After the three sites were scouted, Brashin selected Site B for the shield generator. Tantor's force eliminated the Ewok city on the site in preparation for the arrival of the Imperial engineers.