Anna Maria of Ostfriesland
Anna Maria of Ostfriesland (23 June 1601 – 15 February 1634) was a German noblewoman. She was a daughter of Count Enno III of East Frisia and Anna of Holstein-Gottorp. Her paternal grandmother was Katharina of Sweden, a daughter of Gustav I of Sweden and his second wife Margareta Leijonhufvud. On 4 September 1622 she married Adolf Frederick I, Duke of Mecklenburg-Schwerin (1588–1658). They had the following children: