Siemowit III, Duke of Masovia
type: Person
description: Polish nobleman
birth date: 1314-01-01
death date: 1381-06-16
death place: Duchy of Masovia
nationality: Poland
parent: Trojden I, Duke of Masovia
parent: Maria of Galicia
spouse: Euphemia of Opava
spouse: Anna von Münsterberg
children: Margaret of Masovia
children: Janusz I of Warsaw
children: Siemowit IV
children: Henry of Masovia
children: Euphemia of Masovia
children: Stanisław Siemowit of Masovia
sibling: Eufemia of Masovia
sibling: Bolesław Jerzy of Mazovia
sibling: Casimir of Masovia
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  value: Bolesław Jerzy of Mazovia
additional property: PropertyValue
  property ID: P3373
  value: Casimir of Masovia
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value: +1314-01-01T00:00:00Z
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value: 4767
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source: Freebase Data Dumps
stated in qid: Q15241312
pub year: 2013

source: Sejm-Wielki.pl
stated in qid: Q93482363

stated in qid: Q24415113

wikidata id: Q2132097
domain: human
level: standard
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data source: Wikidata (CC0 / public domain)
license: https://creativecommons.org/publicdomain/zero/1.0/
api version: v1
served at: 2026-08-01T14:58:59.418527Z
entity updated at: 2026-04-10T23:36:04.254244+00:00Z
entity created at: 2026-04-10T23:36:04.254244+00:00Z