The life and works of the King of Kartli, Vakhtang I Gorgasali (c. 440-502), a dominant figure in Georgian history and historiography of the second half of the fifth century, still present unresolved enigmas even after more than 150 years of research. The same is true of his ecclesiastical reform which introduced the katholikosate. The present study provides an overall view on this issue, and, by means of a new interpretative reading of events passed on to us by Georgian, Byzantine, Armenian and Syriac historiography, we can conclude that the reform was preceded by a confessional conflict between King Vakhtang, a pro-monophysite, and Bishop Michael of Kartli, a Chalcedonian. Implemented between April 475 and February-March 476, the reform resulted in a substantial political and ecclesiastical reorganization of the Church of Kartli, crowned by the establishment of its autocephaly and the appointment of the katholikos as the sovereign leader of the Church in a State that lay beyond its imperial borders.