pˈeɪtɹɪˌɑːɹk ˈɛmstˈaɪslæv pˈɜːsənəli sˈaɪnd ænd ɐfˈɪkst hɪz sˈiːl tə ðə mˈɜːdʒɚ dˈɑːkjuːmənts, wˌɪtʃ fˈɔːɹmd ðə juːkɹˈeɪniən ˈɔːɹθədˌɑːks tʃˈɜːtʃ ʌvðə kˈɪɪvˌæn pˈeɪtɹɪˌɑːɹkeɪt ˌʌndɚ hɪz lˈiːdɚʃˌɪp, bˌʌt ðə stˈæɾəs ʌvðə nˈuː tʃˈɜːtʃ æz wˈɛl æz ðɪ ˌoʊvɚɹˈɔːl sˌɪtʃuːˈeɪʃən wɪððɪ ˈɔːɹθədˌɑːks fˈeɪθ ɪn juːkɹˈeɪn bɪkˌeɪm ɐ sˈʌbdʒɛkt ʌvðə wˈaɪd kˈɑːntɹəvˌɜːsi sˈiː hˈɪstɚɹi ʌv kɹˌɪstɪˈænᵻɾi ɪn juːkɹˈeɪn, wˌɪtʃ ðə pˈeɪtɹɪˌɑːɹk wʌz ʌnˈeɪbəl tə ɹᵻzˈɑːlv wɪðˌɪn hɪz lˈaɪftaɪm.
Patriarch Mstyslav personally signed and affixed his seal to the merger documents, which formed the Ukrainian Orthodox Church of the Kyivan Patriarchate under his leadership, but the status of the new church as well as the overall situation with the Orthodox faith in Ukraine became a subject of the wide controversy (see History of Christianity in Ukraine), which the patriarch was unable to resolve within his lifetime.