In Greek mythology, Lynceus (; ) was a prince of Egypt and king of Argos, succeeding Danaus on the throne. Through his marriage to the Danaid Hypermnestra, he began the Danaid Dynasty that led to Perseus, hero and legendary founder of Mycenae.
Family
Lynceus was one of the 50 sons of King Aegyptus of Egypt. Aegyptus had many consorts, and Lynceus was one of six sons born to Argyphia, a woman of royal blood. His five full brothers are named as Proteus, Busiris, Enceladus, Lycus, and Daiphron. Aegyptus was the son of Belus and either the naiad Achiroe, daughter of the river god Nilus, or Sida, eponym of Sidon. He was the twin brother of Danaus, an Argive king and father of the 50 Danaids.
Mythology
Lynceus's father Aegyptus commanded that his 50 sons should be able to marry his brother's 50 daughters, the Danaids. However, though Danaus agreed to the arrangement, he was greatly angered by his brother's actions. He gave all the Danaids swords and instructed them to kill their husbands after they had fallen asleep on their wedding night. The next morning, they were to bring their husband's heads to him as proof of the deed.
However, while all 49 other Danaids followed through and killed their husbands, Hypermnestra alone refused. In the most common version of the myth, she decided to spare Lynceus when he honored her wish to remain a virgin. After sparing her husband, Hypermnestra helped Lynceus flee back to safety either with his father in Egypt or to Lynceia, a city in Argos. In the version of the myth where he flees to Lynceia, Lynceus informed his wife of his safety by lighting a torch: she then informed him of her safety by lighting a torch from Larissa, the citadel of Argos. The city was later named Lynceia in his honor.
When Lynceus arrived back in Egypt, he informed his father of Danaus's treachery and his brothers' deaths. They raised an army and sailed to Argos, where Lynceus killed Danaus, united with Hypermnestra, and became king. According to Apollodorus however, there was no invasion and Lynceus did not kill Danaus; instead, Lynceus was passed the crown after Danaus's eventual death.