Siegfried IV was the last Count of Northeim-Boyneburg and Homburg. He gave the land at Amelungsborn for the foundation (in the 12th century) of the future Amelungsborn Abbey, a Cistercian monastery, which was officially settled by a community of monks from Altenkamp Abbey.
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Siegfried IV, Count of Northeim-Boyneburg and Homburg Wikipedia(Text) CC BY-SA