The daughter of Wacław III Adam and his second wife, the Princess of Saxony, Katarzyna Sydonia. Maria Sydonia was the first wife of the Prince of Legnica, Fryderyk IV. She died in childbirth on the night of 2 October 1587 and was buried on 17 November 1587 in the church of St. John in Legnica.

(F. W. Sommersberg, vol. 1, p. 741, K. Jasiński, Rodowód, pp. 202-203)