He founded a monastery at Ḥirta sometime after the death of Aba (552).
[1][2] Cyrus was one of the earliest Syriac authors to write liturgical commentary of the "cause" or explanation (ʿeltā) genre.
[1] His work completed that begun by Thomas of Edessa on the feasts of Nativity and Epiphany.
Like Thomas, he was influenced by the theology of Theodore of Mopsuestia.
[2] In his explanation of the Fast, Cyrus writes that "[fasting] appears with the Manichaeans, the Marcionites, Macedonians, Valentinians, and Katharoi (qtrw), together with all of the Mandaeans, the Kentaeans, and those like them."