By the end of Catherine II's reign, roughly half of this population was converted, with 1.5 million Uniate faithful remaining (mostly in Volhynia and Belarus).
[4] In 1827, Semashko wrote a memorandum advocating for the unification of remaining Uniate parishes in the Russian Empire with the Orthodox Church.
[5] In Uniate churches, whose appearance and equipment had undergone Latinisation in the previous decades,iconostases, Orthodox utensils, and liturgical vestments were restored.
[5] In 1835, Semashko was invited to join a secret government committee charged with bringing about the unification of the Uniate and Orthodox Church.
[4] By the end of the year, Semashko had already submitted a memorandum arguing for starting the reunion, and the Orthodox metropolitans of Moscow and Kyiv quickly agreed.
The meeting, known as the Synod of Polotsk, adopted the Act of Reunion and issued an appeal to the tsar (prepared by Semashko) that would result in the transfer of 1,600 Uniate parishes and the incorporation of 1.5 million parishioners into the body of imperial Orthodoxy.
[1][6] Afterward, Semashko declared of himself, "The Lord, having chosen his instrument for the completion of this noble deed, animated him with insuperable fervor and gave him powers to overcome all obstacles.
In his drive to enforce decisions of the Synod of Polotsk, Semashko relied mainly on persuasion and manipulation against the clergy and parishioners, but he did not hesitate to utilize administrative and police repressions against Greek Catholics who refused to convert.
He confined the reluctant Basilians to a specially created monastery prison in Kursk which existed until 1842, other priests indicated by him were deprived of parishes, and some were deported to Siberia.
[2] He complained about the influence Roman Catholic clergy and nobility had on the civil administration of the area, and in 1851 wrote a long letter to the emperor asking for permission to resign.
[2] With the death of Nicholas I, Semashko's influence in the Holy Synod diminished, but he continued his struggle against the Catholic Church in the Western Krai.
In February 1859, through the Ober-Procurator of the Holy Synod, he sent a note warning Tsar Alexander II about the undesirable consequences of the conciliatory policy towards the Polish people and Catholicism in the Western Territory.
[2] In 1863, during the Polish uprising, he consistently supported the Imperial government, appealing to his flock to remain faithful to the Russian Tsar and the Orthodox Church.
In 1883 his autobiography and a collection of documents associated with his life were published as Zapiski Iosifa, Mitropolita Litovskago (The Notes of Yosyf, Metropolitan of Lithuania, 1883, 3 vols).
She stated that in 1838 Semashko personally ordered the forced conversion of the nuns of the convent and that when they refused had them imprisoned, starved, flogged, sexually assaulted, and repeatedly tortured.
[11] Although Russian Foreign Office diplomats and Metropolitan bishop Yosyf Semashko himself adamantly denied Mother Makrina's story, it was widely believed, including by Pope Gregory XVI and his successor Pius IX.
Edmund Maykowski published some documents, namely her correspondence with Cardinal Ledochovski and the official report of the commission appointed by the Archbishop of Poznan Przyluski.