Sabina Catherine of East Frisia Countess of Rietberg (1582–1618) Parents Enno III, Count of East Frisia Walburgis, Countess of Rietberg Children Ernest Christopher Johann Cirksena Siblings Agnes of Ostfriesland Anna Maria of Ostfriesland Ulrich II, Count of East Frisia Rudolf Christian, Count of East Frisia Christina Sophia of East-Frisia Partners John III of Rietberg