Which renowned concert pianist served as Poland's prime minister in 1919?

At his death in 1865, which assassin was supposedly engaged to Lucy Hale, daughter of a former U.S. senator? At his death in 1902, who left most of his fortune to fund scholarships for study at Oxford University? At his death in 1915, which educator was buried on the campus of the Tuskegee Institute he led? At his death in 1931, which New Jersey-based inventor held more than a thousand patents? At his death in 1971, more than 1,600 department stores bore which merchant's name? At his death in 1995, which polio vaccine developer was working on a vaccine to prevent full-blown AIDS? At his death in April 1955, whose brain was preserved and whose ashes were reportedly scattered in the Delaware River? At his death in March 1848, who left a fortune of about $20 million made in the fur trade and real estate?