Peter III of Russia
On 21 February 1728, Anna gave birth in Kiel Castle to a son named Carl Peter Ulrich, the future Peter III of Russia. Peter would found the House of Holstein-Gottorp-Romanov that would go on to rule Russia until the early 20th-century. A few days after his birth, the barely twenty-year-old duchess caught puerperal fever (postpartum infection) and died on 4 March 1728. In memory of his wife, Karl Friedrich founded the Order of St Anna, which subsequently became a Russian decoration.