http://fmg.ac/Projects/MedLands/BRUNSWICK.htm

  HELENE von Braunschweig (18 Mar 1223-6 Sep 1273, bur Wittenberg Franciscans).  The Cronica Principum Saxonie names (in order) "Mechtildim…Helenam…Alheidem…Helenam" as the daughters of "Ottonem de Lunenburch" & his wife, specifying that the first "Helenam" married firstly "Hermannus dominus Hassie, filius beate Elisabeth" and secondly "Albertus dux Saxonie"[89].  The Annales Stadenses records the marriage "1239 die Dyonisii" of "Hermannus filius sanctæ Elizabeth" and "Elenam filiam ducis Ottonis de Brunswich"[90].  The Annales Sancti Pantaleonis Coloniensis record that "Hermannus landgravius filius sancte Elysabeth" married "filiam ducis de Brunswich"[91].  The Cronica Principum Saxonie names "Helenam filiam Ottonis de Brunswick" as third wife of "Albertus dux"[92].  She founded the Kloster of the Franciscan Order at Wittenberg.  m firstly ([9 Oct 1239]) HERMANN II Landgraf of Thuringia, son of LUDWIG IV "der Heilige" Landgraf of Thuringia & his wife Elisabeth of Hungary (-Kreuzberg 3 Jan 1241).  m secondly ([1247/48]) as his third wife, ALBRECHT I Duke of Saxony, son of BERNHARD I Duke of Saxony, Graf von Aschersleben und von Anhalt & his wife Judyta of Poland (-[27 Sep/7 Nov] 1260, bur Lehnin).