Cassian Sakowicz was the son of an Orthodox priest. He studied at the Zamojski Academy and Jagiellonian University at the ruler's court in Przemysl, under King Athanasius' protection. Sakowicz was the rector of the School of Bracka in Kiev from 1620 to 1624. In 1624, he moved to Lublin and in 1625 converted to Catholicism. From 1626 to 1639, he was in the Archimandrite Monastery of the Exaltation of the Lord in Dubno, where he was responsible for his duties as supervisor. He also had accepted the Union of Brest. In 1641, with the permission of Pope Urban VIII, he changed to the Roman rite and was the chaplain of the Augustinian monastery in Krakow. Sakowicz died in 1647.
- Bibliography of Polish Literature - New Korbut, Vol 3 Old Polish Literature, State University Press, London, 1965, pp. 198–199
- Енциклопедія українознавства, т. 7, Львів 1998, с. 2,692.