In the “Armenian Book of Canons,” codified firstly in 719, under No. 42 are listed nine “Canons of the Holy Council convened in Theodosiopolis, which is now called Karin.” The preamble of its Protocol speaks of the Armenian-Romano-Byzantine joint council, which took place at the behest of Emperor Justinian and under the chairmanship of the Armenian Catholicos Sahak. Since the time of the Armenian Patriarch of Constantinople Malachia (1896–1908), there has been an opinion that this refers to Justinian II (685–695, 705–711) and Sahak III Dzoraporetsi (677–704), since two of the nine rules were allegedly not relevant in earlier eras. Vazgen Hakobyan, who edited the “Armenian Book of Canons” (1964–1971), in view of the absence of data about these “Canons of the Holy Council…” in medieval literature, as well as the peculiar definition of the dogmas of Orthodoxy in the preamble of its Act, declared that this document was a “fake original.” However, the analysis of the same two rules, indirect references to three rules in the letter of Stepanos, Bishop of Syunik‘ (d. 735), addressed to Antioch, the analysis of the context of the preamble of the Synodal Act, and indirect references in two narrative sources to the convening of such a council, allowed A.K. Shahinyan not only to prove their authenticity. As he demonstrated, “The Canons of the Holy Council convened in Theodosiopolis…” could well have been adopted under the chairmanship of Catholicos Sahak II Ułketsi (534–539) and by order of Emperor Justinian I the Great (527–565) in 534 or 535. The definition of the dogmas of Orthodoxy in them was completely consistent with the spirit of the so-called “unforeseen” theological decree of Justinian I of 533.