number of their congregations quickly swelled from 20 in 1555 to 64 in 1570. Their main centre was the city of Leszno, where they were settled under the patronage of the devotedly Reformed Leszczyński family. Thus the Greater Poland Brethren (Jednota Wielkopolska) also called the Czech Brethren, was formed. The Greater Poland and the Lesser Poland Brethren did try to cooperate more closely and even signed in 1555 a Union agreement but the Lesser Poland's Reformed nobles who formed the bulwark of the church members found the Czechs to be too hierarchical and undemocratic, and in the end the Lesser Poland Brethren became a strongly synodal structure, while the Greater Poland church became more Presbyterian. The Reformation in the Grand Duchy of Lithuania (today's Lithuania, Belarus, and Ukraine) date to 1552 when the local aristocrat Mikołaj "the Black" Radziwiłł received a Reformed preacher, although some of Reformation ideas were known in Sigismund II Augustus palace because of returned educated Lithuanian Abraomas Kulvietis, who had founded school and taught children in Lutheran manner. He was generally unpopular among the Catholic hierarchy because of his Lutheran beliefs, and when the queen was away in 1542 Abraomas was forced to leave the country. Soon he (Radziwiłł "The Black") was followed by his cousin Mikołaj "the Red" Radziwiłł and other aristocrats. The first synod was held in 1557, and two years later the Lithuanians signed a Union agreement with the Lesser Poland Brethren. A huge number of converts were attracted from Orthodox nobility. While the nobles used Polish in church services, an effort was made to convert the Lithuanian-speaking peasants and serfs, but since Lithuanian did not have a written form till the second half of the 19th century, Polish stayed as the official church language. Thus, the Lithuanian Brethren (Jednota Litewska) came into being. In 1556, John a Lasco (Jan Łaski) returned from Western Europe to help with the organisation of the Polish Reformed church. Seeing that the new king Sigismund II Augustus was sympathetic to the Calvinist cause, he tried to write a confession that would be agreeable not only to all the three Calvinist churches but to the Lutherans as well. Unfortunately, exhausted from overwork, he died in 1560, having achieved only the consolidation of the Lesser Reformed Brethren, which shortly afterwards was weakened by the split of the Unitarians (1563). In the same year, the Second Helvetic Confession was translated