Jacob Johan Anckarström

Jacob Johan Anckarström (1762–1792) was the Swedish captain who murdered King Gustav III. A former page and captain in the king's regiment, he was embittered by the Union and Security Act of 1789 stripping the nobles of privilege. With Counts Horn and Ribbing he conspired, and on 16 March 1792 shot the king at a masked ball in Stockholm's Royal Opera. The king had received an anonymous warning but attended anyway.

Gustav III died on 29 March. Anckarström confessed, was condemned to flogging, loss of his right hand and beheading, and was executed on 27 April 1792.