The Council of Florence
The apparent desire of Rome to end the Eastern schism was reflected at the ecumenical Councils at Basel 1431, Ferrara 1438, and finally in Florence 1439. At the Council in Basel Pope Eugenius IV (14321-1447) requested that the Byzantine Emperor, the King of Poland and the Grand Duke of Lithuania participate at the Council in order to enter the negotiations for the Church reunion. The Emperor and the Patriarch of Constantinople were interested in entering such dialogue, having also the legate of the Church of the Kiev-Ruthenian Rite1 at the Council. For this reason Svidrygello (1430-32), the Grand Duke of Lithuania, sent Harasim (1432-35), Bishop of Smolensk, to Constantinople in order to be consecrated as the Metropolitan of Kiev by the Patriarch Joseph II. A war was going on in Lithuania between the Catholics supporting Duke Sigismund (1432-40), and the Orthodox supporting Svidrygello who, being provoked by the suspicion that Harasim was plotting against him, ordered to burn him alive in Vitebsk in 1435. This tragic event triggered unfortunate consequences for Svidrygello, who suffered a crushing defeat from his own supporters. The successor of Harasim, the abbot of St. Demetrius Monastery in Constantinople, Isidore (1436-63) a well known ecumenical promoter, initiated the idea of Muscovite participation in the religious dialogue with Rome. For this reason Isidore left Constantinople in 1437 for Ferrara via Moscow. It seems to us that Isidore was of the opinion that if the Muscovite Orthodox Church would accept the union with Rome, the whole East would accept it automatically. As shown later, lid ore’s idea was wrong, because the Church union should have originated from Kiev, not from Moscow. This he realized later, and after long talks with Basil (1425-33), the Grand Duke of Muscovy, Isidore was not granted permission to represent the Russian Orthodox Church at the Council unless he would accept the first seven ecumenical synods which, according to the Muscovite Orthodox teaching, were the only ones legal and recognized by theChurch. With such a mandate Isidore left Moscow accompanied by over two hundred Russian and Greek clergy, including his later successor, Gregory. On his way to Ferrara, Isidore decided to see the Orthodox clergy of his metropolia in order to seek their formal consent to represent the whole Kievan Metropolia at the Council. Unfortunately, Sigismund, the Grand Duke of Lithuania, refused permission for Isidore to travel across his country. Forced by the circumstances, Isidore continued his journey through Novgorod, Dorpat, Nuernberg, Bavaria, Tirol, and on August 20, 1438 arrived at Ferrara as «Metropolitan of Kiev and all Russia». It was to be expected that the Grand Duke of Lithuania, Sigismund, would not participate at the Council of Florence as he was at odds with his supporters after the removal of his rival Svidrygello. There were no representatives from Poland either, despite the fact that Pope Eugenius IV had twice invited the primate of Poland, the Bishop of Gniezno, to attend the Council, although the bishop was in favor of the Council of Basel.
On Monday, March 2, 1439, Latins and Greeks met for the first time in a joint session in Florence. The main issue of the discussion was the dogma of the Holy Trinity which Latin theologians had formulated stating that the Holy Spirit proceeds from the Father and the Son. The Greek theologians indicated that the Scripture clearly asserts that the Holy Spirit proceeds from the Father alone. The dogmatic discussion among the synodal fathers was useless and jeopardised the whole outcome of the Synod. At this time Isidore appeared at the Council and with his knowledge, his power of persuasion, and his ability of compromise, managed to bring the discussion to an end. On July 6, 1439 the union between Latins and Greeks was signed, and the decree of union «Laetentur caeli» was issued by Pope Eugenius IV, which defined the problem of «filioque» as follows: «In nomine Sanctae Trinnitatis, Patris et Filii et Spiritus Sancti, hoc sacro universali approbante Florentino Concilio diffinimus, ut haec fidei veritas ab omnibus christianis credatur et suscipiatur, sicque omnes profiteantur, quod Spiritus Sanctus ex Patre et Filio aeternaliter est». (Denz-Rahner n. 691).
The Receipt of the Union by the Eastern Orthodox Christendom
On September 4, 1439, Isidore set out on his long journey back to Russia as Apostolic legate in the provinces of Lithuania, Livonia, Russia and territories of Lechia, which were recognized as being subject to his rights as metropolitan. Isidore left Venice on December 9, 1439, having in the meantime been named Cardinal, and on March 5, 1440, he reached Buda. Isidore’s task was very difficult, namely, to obtain acceptance of the Union of Florence from all the Orthodox Christians included in the metropolia of Kiev and all Russia. In Buda Isidore issued an encyclical letter, announcing the union of the Western Church with the East which restored again the ancient unity of the Church. From Buda he went to Cracow (April 5, 1440), where he met Ladislas who was prepared to depart for Hungary. The King recognized Isidore’s rights as the Metropolitan of Galicia, where in May of 1440 Isidore proclaimed the Union of Florence, and from where he proceeded to Kiev his primatial See. He remained there for over two months preaching the union and commemorating the pope in the liturgy.
After arrival at Vilno, Isidore visited Lithuanian Bishop Mathias, who was still a supporter of the Council of Basel. In spite of the fact that Isiore was a papal legate, he was not given permission by Bishop Mathias to proclaim the Union of Florence in Lithuania. Consequently, he left for Kiev where Prince Olelko (1443-54), the Grand Duke of Kiev, recognized the Union of Florence, together with the Monastery of the Caves. On February 5, 1441, Olelko submitted the entire metropolia to the jurisdiction of Metropolitan Isidore. Continuing his final trip to Moscow, Isidore stopped at Smolensk, an ecclesiastical center of the Byelorussians, and persuaded the local Prince George to accept the Union of Florence. The traditional desire for unity with Rome which dominated the religious aspirations of the Kievan Rus’ contributed in great extent to Isidore’s success. As stated previously, Isidore left for Moscow with the instruction not to bring back any new decrees of the Florentine Council which were contrary to the Muscovite Orthodox teaching. In addition, Basil believed that Constantinople had accepted union with Rome because it needed the help of the Latin Church against the Turkish attacks. Acceptance of the union by Basil would have meant subservience to the pope and acceptance of a coalition with Poland, Lithuania and all Rus’ lands, which had heretofore opposed him. After arriving in Moscow on March 19, 1441, Isidore, in spite of all difficulties, was able to appear as the «Metropolitan of Kiev and all Russia». By virtue of authority given to his office, Isidore ordered that the decrees of the Union of Florence be read in the Moscow Cathedral during the solemn Mass. The tragic consequence followed immediately. The Grand Duke Basil interrupted the reading of the decrees, accusing Isidore of heresy because of the new teaching about the Holy Spirit, purgatory, etc. He ordered Isidore to be arrested and placed in the Chudow Monastery in the Kremlin. Isidore realized that the failure of his mission was to be followed with political and religious consequences. The following month Isidore escaped from the prison with his companion Gregory and left for Catholic Lithuania and Poland although the attitudes of the government and the Church were still in favor of the Council of Basel. For this reason Isidore departed for Kiev, where he received a most welcome reception as the lawful head of the Kievan Metropolia. Indeed, the time for the reunion of the Kievan Metropolia with Rome was very favorable, and Isidore should have stayed in Kiev longer time to work for the reunion of all Eastern Church with Rome, from a city which had been called the «Mother of the Christian East», However, being of Greek origin, Isidore believed that the union between Constantinople and Rome must be completed first, and then the whole East would accept it automatically. Consequently, Isidore left for Rome. On his way he stopped at Peremysl to consecrate the first uniate bishop of the Kiev-Ruthenian Rite.
At Buda Isidore met with the Polish King Ladislaus (1434-44) and requested his support of the Union of Florence in Poland. Undoubtedly, at Isidore’s persuasion Ladislaus III issued in Buda on March 21, 1443, the document of formal recognition of the Union of Florence. The King clarified thereby also the legal status of the Ruthenian Church in the Polish State by granting it full equality with the Latin Church in accordance with the Union of Florence. In Siena Isidore met with Pope Eugenius IV in order to make a report on his trip to the lands of the Orthodox faith. The Pope recognized his efforts in the cause of the reunion of the Churches and advised him to return to the Grand Duchy of Muscovy, but this time via Constantinople. On August 28, 1443, Isidore left for the area of his jurisdiction which he was never to reach. In the meantime the crusade against the Ottoman Empire had been launched by King Ladislaus of Poland and King Janos Huniady of Hungary with the assistance of Cardinal Cesarini, who brought with him some two hundred armed men. Unfortunately, however, the whole crusade ended with the unexpected defeat at Varna on November 4, 1444, where all three lost their lives. The failure of the crusade against the Turks had obviously negative consequences for the Church as well as for the defense of all Christendom. The spirit of the Union of Florence remained still alive, chiefly due to the fact that the new Patriarch of Constantinople, Gregory Mamma (1446-50), elected in July of 1445, strongly supported Isidore despite the fact that the Union of Florence had not been officially proclaimed in Constantinople. The opposition against the union was growing in the Grand Duchy of Muscovy. Basil II being informed that some Greeks were in disagreement with Rome, decided with the help of the Byzantine Emperor to replace Isidore with another Metropolitan, faithful to the Muscovite Church. The negotiations had not progressed far, when upon Basil’s request a synod of the Muscovite Orthodox Church was called to Moscow on December 15, 1448, when Bishop Iona was elected the Metropolitan of Russia with the consent of the Byzantine Emperor Constantine XIII. This decision of Basil II was an obvious step to make the Muscovite Church independent of Constantinople, and was thereby the beginning of the autocephaly of the Muscovite Orthodox Church. Patriarch Gregory Mamma realized that opposition to the Union of Florence was growing stronger in Constantinople. The open appeal of Pope Nicholas V (1447-55) to the Emperor asking for recognition of the Union of Florence in the Byzantine Empire did not help Patriarch Mamma, who, consequently, because of the Turkish attacks, was forced to depart for Rome.
In 1452 Isidore arrived at Constantinople for the third time in order to support his followers. This time he managed to proclaim the Union of Florence at St. Sophia’s Cathedral on December 12, 1452 in the presence of the Emperor Constantin and over three hundred Church dignitaries. His success would have been much greater if only he had promised the Byzantine Emperor effective assistance against Turks. Pope Nicholas V (1447-55) sent another legate, the Archbishop of Ragusa, Jacob Veniero, with a fleet of ten galleys and a few other ships from Naples, Genoa and Venice against the Turks. Unfortunately, this armada arrived too late. Constantinople had already fallen into Turkish hands on May 29, 1453. On this occasion Metropolitan Isidore, having left Constantinople during the siege, wrote to Cardinal Bessarion that the fall and ruins of Constantinople could not be compared even to that of Troy of Jerusalem. It was obvious, however, that the fall of Constantinople was a tremendous blow to the whole unifying action of Isidore for centuries to come. From now on, the new Patriarch, confirmed by the Muslim sultan, was to follow the sultan’s orders. To be sure, Mohammed II (1430-81) confirmed on this office on June 1, 1453 the monk Gennadius (1453-57), who turned against the Union of Florence, even though the legal Patriarch of Constantinople, Gregory Mamma, lived in Rome. With obvious satisfaction, the Muscovites interpreted the fall of Constantinople as a punishment of the Greek Orthodox Church for having made the union with Rome. On the other hand, they felt that they were the only lawful successors of Eastern Orthodox Christendom.
The position of the Orthodox Church in the Kievan Rus’ was diametrically different to that taken by the Muscovite Orthodox Church. The Church was still in favor of the Union of Florence and the Diocese of Halych was under Roman jurisdiction. Upon Isidore’s suggestion, on January 16, 1458, the Pope named Macarius of Serbia to bishop of Halych.
Halych has been the ecclesiastical center of jurisdiction of a Ruthenian princesses, as well as traditional religious center of Ruthenians of Greek rite. Therefore, Pope Calixtus III wrote to the Polish king, asking him to protect Macarius in exercising his pastoral duties, having in mind that Halych accepted decrees of the Council of Florence. It is important to remember that Halych, Peremysl and Cholm were situated within the Polish Realm, while Archbishop of Polotsk, bishops of Briansk, Smolensk, Turiv, Lutsk and Volodymyr were annected into the Metropolitan See of Kiev as an autonomous Ruthenian church in the Duchy of Lithuania.
There appeared now a great problem for Calixtus III (1455-58) to solve, namely, the division of the Kievan Metropolia into two independent ecclesiastical bodies. Upon Isidore’s recommendation, he divided, on July 21, 1458, the Kievan Metropolia into the Muscovite part «occupied by schizmatics and rebels» and the Church of Kiev, later called the «Kiev-Ruthenian Rite» with all parts of Lithuania and «Inferior Russia», placed under the jurisdiction of «the Archbishop of the Ruthenians» which was to be exercised by the Archbishop-Metropolitan Gregory, known in the history of the Ukrainian Orthodox Church as «Hryhoryj Bolharyn», monk from Constantinople and companion of Isidore, appointed to that office by Pius II on September 3, 1458. The recognition of Metropolitan Gregory by the Polish-Lithuanian State and the Ukrainian episcopate had as one of the effects the final separation of the Church of Moscow as an independent metropolia from the Kievan Metropolia. This crucial decision of Calixtus III laid the legal foundation for the final separation of the old Kievan Metropolia into two parts: The Kievan, with Ukrainian-Byelorussian Church in the Polish-Lithuanian State, and the Muscovite, which became a patriarchate in 1589. On August 6, 1458, Pope Calixtus III died and his successor Pope Pius II (1458-64) issued the bull in which, with reference to the decretal of Calixtus III of July 21, 1458, he requested that the nine sufragan bishops of the Kievan Metropolia should obey Metropolitan Gregory, and deny obedience to Metropolitan Iona «who acts as Archbishop of all Russia». Metropolitan Gregory soon departed for Kiev to propagate the Union and obtain the expression of loyalty and obedience of his bishops. Unfortunately, the whole mission of Gregory suffered defeat with the death of Patriarch of Constantinople, Gregory Mamma (1459). Pope Pius II replaced him with Cardinal Isidore, who died on April 27, 1463. He, in turn, was replaced by Cardinal Bessarion, Since the Patriarchs resided in Rome, they could not maintain contact with the Kievan Metropolia, which slowly moved back to Constantinople. The final recognition of Gregory by the Patriarch as Metropolitan of Kiev took place shortly before his death, in 1472. It seems that Pope Paul II (1464-71) and Sixtus IV (1471-84), did not show any interest in reunion with the Kievan Metropolia, and did not object to such relations with Constantinople where the Union of Florence was officially repudiated by the Ottoman Empire in 1472.
From Misael to Joseph I.
Despite all the difficulties shown above, the Kievan Metropolitan Misael Prucky continued to work for the Church reunion. At the Synod of Novgorodok (1473), a message was drafted to Sixtus IV asking him for support of their strong desire to reunite with Rome. This letter never did reach Rome, since Bishop Antonio Bonumbre, who had accompanied Sophia Paleologue to Moscow, and who served as messenger of the Synod, had not arrived in the Eternal City. The second Synod was held in Vilno on March 14, 1476, where a new message was written to Sixtus IV asking him to support their efforts to establish Church reunion with Rome. This letter, which was probably drafted by Metropolitan Misael himself, is a long theological tractate stating that they recognized the Union of Florence, the Catholic dogmas, and the supremacy of the pope. The Synod complained, however, about the interference of the Latin rite hierarchy who demanded obedience from the Ruthenian bishops. The political situation was becoming unfavorable for the Catholic Church after the occupation of Novgorodok by Ivan III in 1477, during which he destroyed the city, and robbed all of its wealth. For this reason it would be logical to suppose that the support of the Metropolitan Misael by Sixtus IV would have been the most urgent diplomatic step at that time. Forced by Muscovite pressure, the Lithuanian State abandoned also Pskov, Tver, and Riazan to Ivan III who seized illegally the title of «Emperor of all Russia». Despite all this, the answer from Rome did not arrive. The neglect of Sixtus IV to recognize Metropolitan Misael spelled out the defeat of the entire unionistic movement created at the Union of Florence. Such an interpretation of the above event seems to be logical since none of Misael’s successors were willing to have any relation with Rome and sought confirmation from the Patriarch of Constantinople. It should be noted also that after the death of Sixtus IV, (1484), his successor, Innocent VII (1484-92), started a new policy toward the Duchy of Muscowy by accepting Ivan’s delegation in Rome.
As late as May 1498, the new Metropolitan, Joseph I (1491-1501) sought also to receive the confirmation to the Metropolitan See of Kiev from the Patriarch Joachim (1498-1502, 1504-1505). On this occasion he wrote to the patriarch on various matters concerning the union with Rome and the privileges granted to his Church after the Union of Florence. Finally, in 1500 the Patriarch confirmed Joseph I to the Metropolia of Kiev and all Rus’. Indeed, Metropolitan Joseph I was considered by the Orthodox hierarchy to be very friendly to the whole unionistic idea and a sort of defector from the Ruthenian Orthodox Church, after he decided to seek also the confirmation to the Metropolitan See of Kiev from the Vatican. His decision, however, was entirely justified, providing Vatican. His decision, however, was entirely justified, providing that his predecessor, Metropolitan Gregory, was to be confirmed by the Vatican and the Patriarch of Constantinople simultaneously. There was no question about Metropolitan Joseph’s adjustment to a sort of «modus vivendi» with both sides since three months after receiving the confirmation from the patriarch’s hands he wrote a message to Pope Alexander VI (1492-1503), (Vilno, August 20, 1500) asking him for confirmation to the Metropolitan See of Kiev This letter was presented to the pope by John Sapieha and Erasmus Ciolek with a message from the Grand Duke of Lithuania, Alexander, who recommended Joseph I to the Kievan Metropolia. Metropolitan Joseph recognized in his letter the supremacy of the pope, pledged his obedience to the Holy See and accepted the decrees of the Union of Florence. There were also problems of rebaptism of orthodox subjects when they accepted the Roman rite and the other problems of rite and liturgy, which Sapieha presented to the pope. He spoke also on behalf of Metropolitan Joseph I, asking the Pope to confirm him to the Kievan Metropolia. The Pope accepted all the recommendations presented by Sapieha, refused, however, to recognize Joseph I as lawful Kievan Metropolitan. For this reason he did not reply to metropolitan’s letter. Alexander VI showed no interest in the reunion of the Kievan Metropolia with Rome and was not familiar with its implications. Essentially the Pope was very concerned with the Turkish invasion and considered the whole situation only from that point of view. On May 7, 1501, the Pope wrote to the Grand Duke of Lithuania, Alexander, that Metropolitan Joseph I, who, being consecrated by the «loachimum hereticum» was not the legal Metropolitan of the Kievan See, as the «real» Patriarch of Constantinople, Cardinal John Michele (1497-1503), resided in Rome. For this reason the Pope wrote that if «Joseph I were willing to accept the decrees of the Council of Florence, admit other ecumenical synods, not to deviate from the Catholic faith… he would be confirmed in dignitate metropolica» The Holy Father authorized Bishop of Vilno Albert Tabor to absolve Metropolitan Joseph from all censures incurred because of his errors despite the fact that the Metropolitan’s declaration of obedience was based on sincerity and submissiveness. Accordingly, Pope Alexander VI wrote to the Grand Duke of Lithuania, with reference to the Metropolitan’s request for his confirmation to the Metropolitan See, that all his subjects who accept the Roman faith need not be rebaptized. Reference was made only to those subjects living in the dioceses of Vilno, Kiev, Lutsk and Medlniky in spite of the fact that the dioceses of Lviv, Kholm, Peremysl and Kamenec were also under the jurisdiction of the Kievan Metropolia. Unfortunately, the entire course of action so well formulated by Metropolitan Joseph I, was eventually abandoned by Rome for reasons unknown to present day historians. Regrettably, Metropolitan Joseph I died in late 1501 and there are no indications that his successor, Iona II, made any attempt toward reunion with Rome. With respect to the action taken by Pope Alexander VI, the expectations of the Kievan Metropolia for reunion with Rome substantially diminished. His position can be easily compared with that taken by Pope Sixtus IV, since in both cases no answer was given to the letters of Metropolitan Misael and Joseph I. It is very regrettable that in both cases the Popes were not concerned with the religious reunion of the Kievan Metropolia with Rome.
In essence, it was obvious that the Kievan Metropolitans wanted to remain in religious unity with Rome which they urgently asked. Their efforts in favor of the union deserved every possible support from Rome, where Moscow’s power was turning against the Catholic states and taking advantage of the name «Rus», which was common indication for the whole Metropolia before 1458 claimed the Byelorussian and Ukrainian territories in the Polish-Lithuanian State. Pursuing its aggressive policy, the Grand Duke of Muscovy began to believe in his messianic destiny as head of the whole Orthodox Christendom. Consequently, this illusory messianism created the false theory of Moscow as a «Third Rome». In his letter to the Grand Duke of Lithuania, Alexander, Ivan III indicated himself as «The Emperor of all Rus’» (1493), the title which he «claimed since time immemorial». The revival of Kiev under the Grand Duke Semen Olelkovych (1455-71), posed a serious threat to the messianistic aspirations of Ivan III. Thus, Ivan persuaded the Tatar khan Mengi-gerey to launch an assault against the city, and on September 1, 1482 Tatars invaded and ravaged the city. The Kiev assault was a well designed plan by Ivan III to offset the possible tendency of the city to revive as a future religious and cultural center of the Christian East.
It seems necessary to remember that all the Metropolitans of Kiev, throughout the entire sixteenth century received confirmation only from the Patriarch of Constantinople without protest from Rome. The whole effort of the Kievan Metropolia to accept the Florentine Union ended in failure because of the absence of a native metropolitan and hierarchy at the Council of Florence which could articulate the aspirations of the people. Besides, the Metropolia was regarded as the administrative unit or province of the Constantinopolitan Patriarchate. Yet, in spite of the fact that Isidore was of Greek origin, he deserves special attention from the historical point of view as he championed the equality of rights of the Eastern Catholic and Roman Catholic Churches. Upon his recommendation Pope Calixtus III erected in 1458 the Kievan Metropolia, now independent from the Muscovite Orthodox Church. Finally, after the Polish Union with Lithuania in 1501, the Grand Duke of Lithuania, Alexander, became the Polish King and united all Ruthenian rite dioceses in Poland with the Kievan Metropolia, whose bishops along with the Metropolitan See of Kiev would remain fully independent of the Metropolitanate of Moscow. However, time and again, relations between the Polish Catholic hierarchy and the Kiev-Ruthenian hierarchy were usually at odds over religious and political issues. The definite solution of such an unfortunate problem had to be made by King Sigismund I, who in 1539 transferred the Ruthenian rite bishopric from Halych to Lviv and confirmed to that office the candidate submitted by the Metropolitan of Kiev.. However, most of the other Ruthenian rite dioceses were situated in the Grand Duchy of Lithuania, where the Ruthenian Metropolitan resided.
The new unionistic movement with Rome was to take place at the Union of Brest Litowsk.
* Nicholas Chubaty, Development of the Kiev-Ruthenian Rite. Diakonia. New York, 1969, v. 4 no. 3. p. 257.
 Ivan Wlasowsky, Outline History of the Ukrainian Orthodox Church. New York, 1956, v. 1. p. 112.
 Theodore Frommann. Kritische Beitraege zur Geschichte der Florentinischen Kirchenvereinigung. Hall a S. 1872. p. 143.
 Magnum Bullarium Romanum, v. 3. p. 25. Eugenius Quartus, XXI. Graz, 1964.
 Ivan Wlasowsky, Outline History…, op. cit. p. 113.
 Bohdan Buchynsky, Studii z istorii tserkownoi unii. Lviv, 1908, v. 85. p. 5-50.
 Ibid., p. 33.
 Akty istoricheskie I, 1841. no. 259.
 Gregor Luznycky, Ukrainian Church between East and West. Phila. 1954. p. 191.
 Ibid. p. 179.
 Bohdan Buchynsky, Studii… op. cit. p. 41.
 Kazimierz Chodynicki, Kosciol prawoslawny a Rzechpospolita Polska 1370-1632. Warszawa, 1934, p. 54.
 Gregor Luznycky, Ukrainian Church… op. cit. p. 183.
 Ivan Mirchuk, Istorychno-ideolohichni osnowy teorii III Rymu. Munchen, 1954, p. 19. Series: Teoria tretoho Rymu. Works, no. 4.
 Documenta Pontificum Romanorum Historiam Ucrainae illustrantia I, no. 86. p. 150-151. Analecta OSBM. Series II. Sec. III. Rome, 1953.
 Ivan Wlasowsky, Outline History… op. cit. p. 115.
 Arkhiv Jugo-Zapadnii Rossii. Kiev, 1887, v. 1. pt. 7. p. 199-231.
 Mykhailo Hrushewsky, Istoria Ukrainy-Rusy, New York, 1954, p. 277.
 Albert M. Ammann, Zur Geschichte der Geltung der Florentiner Konzil-sentscheidungen in Polen-Litauen. Orientalis Christiana Periodica, 1942, v. 8. p. 309.
 Mykhailo Hrushewky, Istoria Ukrainy-Rusy, Lviv, 1905, v. 5. p. 537.
 Ibid., p. 538.
 Albert M. Ammann, Zur Geschichte der Geltung… op. cit. p. 309.
 Documenta… no. 104, p. 181.
 Ibid., no. 104. p. 181
 Ibid., no. 108, p. 187.
 Ibid., no. 108. p. 187.
 Mykhailo Hrushewsky, Istoria Ukrainy-Rusy… 1954, p. 277.
 Mykhailo Vavryk, Cardinal Isidor, in Materials for History of the Ukrainian Church. Munich, 1969. p. 57. Series: Sci. Memoirs of the Ukrainian Free University, no. 9-10.
 Oskar Halecki, From Florence to Brest 1439-1596. Rome, 1958, p. 186.