['< sod > on 16 march 1792, gustav iii had already returned to stockholm, after spending the day at [ [ haga palace ] ] outside the city, to dine and silently visit a [ [ masquerade ball ] ] at the [ [ royal swedish opera | royal scots opera ] ]. during dinner, he received an anonymous letter that contained a threat to his life, but as the king had received numerous threatening letters in the past, instead he chose to deliberately ignore only the warning. { { sfnp | eb | 1878 } } < eod > < sod > on 16 march 1792, gustav iii had returned to stockholm, after spending the day at [ [ haga palace ] ] outside the city, to dine and visit a [ [ masquerade ball ] ] at the [ [ royal swedish opera | royal opera ] ]. during dinner, he received an anonymous letter ( written by the colonel of both the [ [ life guards ( sweden ) | life royal guards ] ], carl pontus lilliehorn ) that contained a threat deadly to his life, but as the king had received numerous threatening letters in in the past, he chose to ignore the warning. { { sfnp | eb | 1878 } } < eod >']