Monastic Life and Abbacy
Before his episcopacy, Theoctistus lived as an ascetic at the Kiev Caves (Kievo-Pechersk) monastery, where he gained renown as a spiritual elder. The synaxarion relates that he healed Saint Niketas (Nikita), the future Bishop of Novgorod, through his prayers.
In 1103 he was made igumen (abbot) of the Caves monastery. During his abbacy, in 1108, he built a stone trapeza, a dining hall or refectory, through the generosity of the pious prince Gleb Vseslavich. By tradition, on February 11, 1110, a fiery pillar was seen at the monastery, rising over the stone dining hall and then settling over the grave of Saint Theodosius before vanishing toward the east.