What disease did Mary Stuart, daughter of Frederick II of Denmark, have that eventually cause her death?
Mary Stuart (1605–1607) Mary of England, Scotland and Ireland (8 April 1605 16 September 1607) was the third daughter and sixth child of James VI and I, the first king of a unified England, Scotland and Ireland, by Anne of Denmark, daughter of Frederick II of Denmark and sister of Christian IV of Denmark; her birth was much anticipated. She developed pneumonia at 17 months and died the following year.
John, Prince of Schleswig-Holstein Johan of Schleswig-Holstein (9 July 1583 – 28 October 1602) was the youngest son of Frederick II of Denmark and Norway and Sophia of Mecklenburg-Schwerin. He went to Russia in 1602 as the bridegroom of Boris Godunov's daughter Ksenia (Xenia), but fell ill and died before the marriage could take place.