Frederick I Rietberg
Frederick I was born about 1231 in Rietberg, Westfalen, Prussia.  He died on July 5th, 1282 in Westfalen, Prussia.

 Beatrix Horstmar
Beatrix was born about 1232 in Horstmar, Westfalen, Prussia.  She died on September 24th, 1277 in Westfalen, Prussia.

 Hedwig Rietberg
Hedwig was born about 1249 in Rietberg, Westfalen, Prussia.