The Royal Guards at Drottningholm Palace are around 25 strong.
Cavalry units and the Infantry artillery school were based at barracks at Drottningholm Palace during the latter part of the 19th century. Where the Royal Guards are based today were originally the palace stables. The guard tent at the China Palace in the Palace grounds was previously used by The Royal Guards.
Royal Guards as we understand the name today always guarded the Palace when the Royal Family was in residence at Drottingholm (such as over Christmas periods).
Since the Royal Family moved permanently to Drottningholm Palace in 1981, the Royal Guards have been on sentry duty there all year round.