"Konrad I of Masovia (ca. 1187/88 – 31 August 1247), from the Polish Piast dynasty, was the sixth Duke of Masovia and Kuyavia from 1194 until ...
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his death as well as High Duke of Poland from 1229 to 1232 and again from 1241 to 1243." - (en.wikipedia.org 28.05.2022)
