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In page Ada of Holland, Margravine of Brandenburg:

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In 1184, Otto I founded a nunnery at Arendsee and in the founding charter, Ada appears along with Otto's three sons, giving assent to the foundation.[3] Otto I died in the same year and was succeeded by Otto II, his eldest son by his first marriage.[4] After Otto I's death, she married his son, Otto II, from his first marriage.[citation needed]