"Henry I (August 1267 – 7 September 1322), Duke of Brunswick-Lüneburg, called the Admirable (German: Heinrich der Wunderliche, Latin: Henricus Mirabilis), a member of the House of Welf, was the first ruler of the Principality of Grubenhagen from 1291 until his death." - (en.wikipedia.org 29.10.2020)
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