Theodosius of Kiev

14 August (Translation of relics) Roman Catholic Church

Theodosius of Kiev or Theodosius of the Caves (; ) is an 11th-century saint who brought cenobitic monasticism to Kievan Rus' and, together with Anthony of Kiev, founded the Kiev Caves Lavra (Monastery of the Caves). A hagiography of Theodosius was written in the twelfth century.

Theodosius' greatest achievement has been the introducing of the monastic rule of Theodore the Studite in the Monastery of the Caves whence it spread to all the monasteries of the Ukrainian and Russian Orthodox Church. According to the Primary Chronicle:

When Theodosius took over in the monastery, he began to practice abstinence, fasting, and tearful prayer.... He also interested himself in searching out monastic rules. There was in Kiev at the time a monk from the Studion Monastery named Michael, who had come from Greece.... Theodosius inquired of him the practices of the Studite monks. He obtained their rule from him, copied it out, and established it in his own monastery to govern the chanting of monastic hymns, in making reverences, reading of the lessons, behavior in church, the whole ritual, conduct at the table, proper food for special days, and to regulate all else according to prescription.

After obtaining all this information, Theodosius thus transmitted it to his monastery, and from the latter all others adopted the same instruction. Whereas the Monastery of the Caves is honored among the oldest of them all.}}

According to the Life of Theodosius by Nestor the Chronicler:

Theodosius has been glorified (canonized) as a saint by the Russian Orthodox Church. His main feast day is 3 May, the date of his repose. His relics were discovered by Nestor the Chronicler on 14 August 1091, and were found to be incorrupt. The relics were transferred to the main catholicon (cathedral) of the monastery, and a second annual feast day was established in commemoration of this event.