Monastic life at Cernica
Constantine entered Cernica in 1807 at the age of twenty and was tonsured a monk on November 9, 1808, taking the name Callinicus. His progress in the community was rapid: he was ordained deacon in December 1808 and priest in February 1813, and was eventually elevated to the rank of archimandrite by Metropolitan Dionysius Lupu.
After the death of his predecessor as superior, the brethren elected him igumen on December 14, 1818, when he was about thirty years old. He went on to govern Cernica for thirty-two years, in addition to overseeing other monasteries and sketes and supervising a number of parish churches. By tradition he kept a severe ascetic regimen, permitting himself only three hours of sleep each day.
Building works
As igumen, Callinicus directed an ambitious program of construction and restoration. The sources credit him with completing a church dedicated to Saint Nicholas on an island at Cernica in under two years and furnishing it fully, and with raising a large church dedicated to Saint George between 1823 and 1836.
He also carried out restoration following the earthquake of 1838, built the church at the Skete of Pasarea (1846–1847) and a church in Buesti, and added stone houses and barns to the monastic establishment.
Episcopate at Ramnicu Valcea
Elected Bishop of Ramnicu Valcea on September 14, 1850, Callinicus accepted the office only reluctantly and held it for roughly seventeen years. As bishop he is recorded as visiting churches and monasteries throughout the diocese and correcting matters that were not in proper order.
He gave particular attention to education and to rebuilding. He opened a seminary at Craiova in 1851 and moved it back to Ramnic in 1854, established schools to prepare church singers, began raising a new episcopal cathedral, and rebuilt an infirmary within the episcopal residence.
Charity and ascetic reputation
By tradition Saint Callinicus died in poverty, having given away what he had to widows and orphans and toward the building of churches and other charitable purposes. The synaxarion accounts also relate that he was credited with healings, with knowledge of others' unspoken thoughts, and with foreknowledge of deaths, including his own.
He returned to Cernica in 1867 and reposed there on April 11, 1868. Metropolitan Niphon conducted his funeral, and he was buried in the narthex of the Church of Saint George at Cernica.