she married on 8 february 1540 in dresden duke francis i of saxe-lauenburg (1510–1581). this relationship turned out to be important for sibylle's brother maurice during the schmalkaldic war. the marriage proved unhappy and francis accused sibylle of "vindictive and unloving acts" in later years, sibylle and francis reconciled again. in 1552, sibylle asked her brother maurice to financially assist her husband, so he could redeem some goods and villages from lübeck.