The autochtonous population of Ukraine had kept a strong sense of identity and had its own nobility, some of whom, like the Ostrogski and Zasławski, were descended from the former rulers of Kiev. They were well equipped to stand at the head of their people, both by their ancient lineage and by their immense wealth. Prince Konstanty Ostrogski (1526-1608) owned a hundred towns and 1,300 villages. Prince Jarema Michał Wiśniowiecki (1612-51) owned 38,000 homesteads, inhabited by some 230,000 of his subjects. But these princes became separated from their people by the lure of Polish culture and Western civilisation. A classic pattern of alienation evolved: it was with the best intentions that Prince Zbaraski travelled in the West and spent three years studying under Galileo, returning to Ukraine to build, fortify and improve, but his people came to view him as a traitor.
The population of Ukraine belonged to the Orthodox Church, whose hierarchy had been shaken by the fall of Constantinople and the subsequent Ottoman expansion in the Balkans, and was still in a state of disarray at the end of the sixteenth century. In 1588 the Patriarch of Constantinople paid a pastoral visit to his flock in the Commonwealth and held two synods, at Wilno and Kamieniec Podolski. Chancellor Jan Zamoyski put forward the suggestion that the Patriarch settle in Kiev and turn it into the centre of the Orthodox Church. Jesuit influence thwarted this, and the Patriarch was invited by Tsar Feodor I to Moscow. There, in 1589, he created the patriarchate of all the Russias, whose purpose was to bring under its authority the whole Orthodox Church, including that part of it which lay within the Commonwealth.
Before leaving, the Patriarch had appointed Bishop Terlecki of Łuck to represent him in Poland. Terlecki started negotiations with his counterpart the Catholic Bishop of Łuck in the hope of achieving greater recognition of his own hierarchy. These negotiations moved on to embrace wider issues and aroused the interest of the Jesuits, particularly of Piotr Skarga. After consultation with Rome, agreement was reached and an Act of Union was signed in 1596 at Brześć. By this act the Commonwealth’s Orthodox bishops recognised the Pope as their spiritual head in lieu of the Patriarch in Moscow, but kept their old Slavonic liturgy and rites, and the right of priests to marry.
The Jesuits congratulated themselves on having brought millions of wayward sheep into the fold, but many Orthodox priests and their flocks felt indignant at not having been consulted, and refused to adhere to the Union, with the result that there were now in effect three and not two Churches—Roman, Orthodox and Uniate, as those who had transferred to Rome were known. While the Roman and Uniate looked to the West, the Orthodox looked elsewhere. The Union had been designed to bind the Orthodox population of Ukraine to Poland. In the event, it had the effect of pushing it into the arms of Moscow. While the Uniate bishops continued in their efforts to bring the recalcitrant priests to accept the Union, the Orthodox hierarchy of Moscow was pulling them the other way.
The organisation of the Uniate Church proceeded slowly. It was not until the 1630s that metropolitan bishops were installed at Kiev and Polotsk, and by then the whole matter was coming under discussion once again. Władysław IV was keen to revise the arrangement within the framework of an entirely new formulation of religious freedoms. He wanted to replace the toleration of differing religions as enshrined in the Act of the Confederation of Warsaw (1573) by some form of ecumenical consensus on religious diversity. After much preparation, he managed to hold a congress at Toruń in 1645, in which Catholics, Lutherans and Calvinists discussed their differences. The congress was inconclusive, but, as the King himself put it, ‘At least nobody insulted each other.’ A similar congress between the Catholic, Orthodox and Uniate Churches was planned for 1648. Meanwhile Metropolitan Mohyla of Kiev was in the process of renegotiating the Union of Brześć with Rome. But these efforts came too late.
The drift of Ukraine’s nobility towards Western culture was usually accompanied by a straightforward switch to Catholicism, which provided a bridge to that culture. In 1632 Jarema Wiśniowiecki, the last of the great Ukrainian lords to live entirely in Ukraine and to cling to its language, culture and traditions, converted to the Church of Rome. Despite the valiant efforts of Metropolitan Mohyla, who founded an academy in Kiev that same year, the Uniate Church was failing to hold people such as Wiśniowiecki, while Orthodoxy was rapidly becoming the religion of the lower orders. It was inevitable that these would eventually see in it a rallying point and a weapon.