YPERMYSTRA, YPERMYSTRE. Hypermnestra was one of the fifty daughters of Danaus and married her cousin Lynceus. Danaus feared his brother Egyptus and ordered his daughters to slay their husbands on their wedding night. Hypermnestra helped Lynceus escape, and Danaus imprisoned her (Heroides XIV).

The Man of Law says that Chaucer commends the wifehood of Ypermystra, Penelope, and Alceste, MLI 75-76. In his version of the story Chaucer switches the fathers and children: Ypermystra is Egiste's daughter, and Lyno is Danao's son, LGW 2561-2575. Venus gave Ypermystra great beauty, but since Jupiter is part of her horoscope, she values conscience, truth, fear of shame, and true wifehood, LGW 2584-2585. Mars's influence was feeble when Ypermystra was born, and she cannot handle the knife to slay Lyno, her husband, LGW 2589-2595. Because of the bad aspects of Saturn, she dies in prison, LGW 2595-2722. [Danao: Egiste: Jupiter: Mars: Saturne]

Chaucer may have been indebted to an Italian translation of the Heroides for the variant form Ypermystra. Latin initial h was not pronounced. Ipermystre, a spelling variant, occurs once, in a medial position, LGW 2663, with elided final -e. Ypermystra occurs once initially, LGW 2575; twice in medial positions, MLI 75; LGW 2594; Ypermystre occurs three times in medial positions with elided final -e, LGW F 268, LGW G 222; LGW 2604, and twice medially with syllabic final -e, LGW 2632, 2647.