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In page Mieszko II Lambert:

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In Merseburg ca. 1013, Mieszko II married with Richeza (b. bef. 1000 – d. Saalfeld, 21 March 1063), daughter of Count Palatine Ezzo of Lotharingia. They had at least three children, and possibly four:

  1. Gertruda (b. 1025 – d. Kiev, 4 January 1108), married by 1043 to Grand Prince Iziaslav I of Kiev.
  2. possibly Agatha, wife of Edward the Exile, whose origins are unknown. One theory that has been put forward is that she was daughter of Mieszko II and Richeza.[1]