Xanthippe and Polyxena were sisters who, by tradition, lived in Spain during the apostolic age and were among the first in their land to receive the Christian faith. The synaxarion relates that they heard the preaching of the Apostle Paul when he came to Spain, and that Xanthippe, together with her husband Probus, accepted Christianity at that time. They are commemorated together on September 23 (September 24 in Slavic usage).
The greater part of their story, as transmitted in the tradition, concerns Polyxena. Before she had been baptized, a man captivated by her beauty is said to have carried her off by force to Greece aboard a ship. There she sought the protection of the Christians and was hidden, and at Patras in Achaia she received baptism from the Apostle Andrew the First-Called. After Andrew's death she returned to Spain, by one account in the company of the Apostle Onesimus.
Reunited, the two sisters are said to have devoted the remainder of their lives to converting the pagans of Spain to Christ. The tradition relates that Polyxena labored about forty years preaching the Gospel, while Xanthippe was active in the populous city of Toledo. Polyxena is said to have preserved her virginity to the end of her life and to have reposed about the year 109.
The narrative of the two sisters derives from the Acts of Xanthippe, Polyxena, and Rebecca, an early Christian apocryphal text generally dated to about the third or fourth century. The events are set in the apostolic generation, and details of chronology and circumstance vary among the surviving accounts.