On May 25, 1878, Gilbert and Sullivan’s comic opera H.M.S. Pinafore opened at the Opera Comique in London. (Image is a detail from an 1879 theater poster.)
On the same date in 1895, playwright, poet and novelist Oscar Wilde was convicted of “committing acts of gross indecency with other male persons” and sentenced to serve two years in prison — becoming history’s most famous prosecutions for homosexual activity.
In 1895 on the 25th of May, the Republic of Formosa was formed, with Tang Jingsong as its president. It lasted less than half a year, dissolving upon conquest by Japan.