Charity and Piety
The Orthodox tradition remembers Theophano above all for her humility and care for the poor. Despite her imperial status she is said to have preferred simple clothing and to have visited the households of the needy, accompanied by only two servants, to offer assistance.
She is credited with building and restoring churches and monasteries and with acting as a mother to her subjects, caring for widows and orphans. After her release from imprisonment she is said to have devoted herself to prayer and fasting.
Family
Theophano was the first wife of Leo VI. Accounts report that the emperor's affections later turned to Zoe Zaoutzaina, who became his mistress. By Wikipedia's account, Leo and Theophano had a single daughter, Eudokia, who died young.
Veneration and the Church of All Saints
Theophano was numbered among the saints soon after her death, and her husband regarded her as holy. As a memorial, Leo VI built a church near the Church of the Holy Apostles in Constantinople, intending to dedicate it to her.
Certain bishops objected to a church dedicated to his wife. According to the tradition, Leo was therefore obliged to rededicate it to All Saints, so that his wife, if she were indeed among the righteous, would still be honored among the many saints commemorated there. Orthodox sources connect this episode with the commemoration of All Saints on the Sunday after Pentecost.
Relics and Shrines
Theophano is venerated as a wonderworker, and tradition holds that she healed the sick whom physicians had been unable to cure. Her relics, described as incorrupt and wonderworking, rest in the Patriarchal Cathedral of Saint George at the Phanar in Constantinople, beside the relics of Saint Euphemia and Saint Solomone.
On her feast, December 16, her relics are reported to be moved to the center of the solea, where the coffin is opened and she is venerated by the faithful. A portion of her skull is kept at Dionysiou Monastery on Mount Athos. The relics are said to have been relocated several times through history, having been transferred by Patriarch Gennadios Scholarios to the Church of the Holy Apostles before eventually reaching the Ecumenical Patriarchate.