In 1457, a group of the faithful led by Brother Řehoř (Gregory) settled in the village of Kunvald u Žamberka. They had left Prague because the practices of the Utraquist Church (the Calixtines) and of the Catholic Church did not satisfy their need for a Christian life lived according to the Bible. The group slowly grew by the addition of further adherents to this basic tenet. In 1467, after an unsuccessful search for an already extant ecclesiastical community, they founded their own church, called the Brothers of God’s Law. This was their definitive break with the Calixtines, and with Jan Rokycana. Life within this community was adjusted to fulfilling the physical needs of Man, meaning that members were not permitted to participate in any undertaking leading to enrichment (trade) or the destruction of life (the military). Administration of the community was entrusted to a Select Council of elders (seniors). The dissimilarity of their divine services and their way of life prompted numerous protests from the representatives of other Churches, but the number of the Brethren’s adherents nevertheless continued to grow. Among members of the nobility, membership was from the beginning secret.
By the end of the 15th century groups of the Brethren existed in Bohemia in the Mladá Boleslav and Hradec Králové districts, around Písek and at Žatec, while in Moravia they appeared in the Prostějov, Přerov and Ivančice districts. The structure and fundamentals of what was now known as the Unitas Fratrum developed along with the growing membership and in the constant defence of the faith. Gradually, members of the Brethren were permitted to participate in commerce, the crafts and in government, of course with the condition that in doing so they did not break God’s law. Over the course of the 16th century sanctions were applied against the Brethren by the offices of the powerful: in 1508, King Vladislav issued a mandate forbidding assemblies of the Brethren, and the texts of the Brethren were to be burnt and their priests compelled to convert to the Utraquist or Catholic Church. The execution of this mandate lasted until 1514. In 1547 the same mandate was renewed, and this was followed by the first wave of emigration on the part of the Brethren; they found refuge for the most part in Poland and Prussia. The numbers of these first religious exiles were swelled by the forced emigration of 1628. It was in this way that the Polish and German branches of the Unitas Fratrum were formed, to which religious exiles of the 18th century fled when the Bohemian Unitas Fratrum could no longer exist even in secret.
In the first period, the most important figure is that of Brother Řehoř himself, the actual founder of the Brethren. In the first phase of its existence he attempted to institutionalise groups of co-believers. Fundamental changes were brought by the establishment of the Unitas Fratrum at the beginning of the 16th century: a “larger party” best represented by Brother Lukáš (Luke) came to the fore. He worked up a new organisational constitution for the Brethren, and developed a confession that showed that the Brethren were not an association of heretics.
After 1547 the congregations of the Brethren in Moravia came to be of greater import; in Bohemia the Brethren lived only on the estates of Brethren nobility at Mladá Boleslav. A general synod was held in 1557 that was also attended by representatives of Polish congregations; a confession was accepted that became the dogmatic norm, and Jiří Izrael (who administered congregations in Poland and Prussia), Jan Blahoslav, Jan Černý and Matěj Červenka were elected bishops. Blahoslav became the spokesman for a new phase in the development of the Unity of Brethren, which was characterised by a greater openness to the surrounding world; above all, it put great emphasis on education. He ensured that youth of the Brethren were send to study at (particularly German) universities and schools abroad. Among his numerous works is an important translation of the New Testament, while the records in the Brethren archive, which was managed and survived at Herrnhut, are indispensable for study of the Brethren’s history. The year 1575 saw the publication of the Bohemian Confession, which set out the differences in faith between the Unity of Brethren and the Lutheran Church. This period was one of promising developments for the Brethren: the Kralice Bible (1576-1594) was published, as was the Hymn Book etc. Another point of conflict arose, however, in 1602, when Rudolf II renewed Vladislav’s Mandate of 1508; a petition, to which Václav Budovec of Budov had contributed a great deal, was unsuccessful. An end to the slighting and attacks from the side of official Church came only with Rudolf’s 1609 Letter of Majesty, which guaranteed the same rights even to the religious beliefs of the Brethren. The unsuccessful Estates Uprising was followed by the expulsion in 1627 of Brethren clergy, and in 1628 of all non-Catholics.
It was during this wave of emigration that Jan Amos Comenius, too, left the country. Protection was offered to Brethren exiles by Raphael V Leszczyński at Leszno, by György I Rákóczi in Hungary and by Krzysztof Radziwiłł at Torun. The Brethren’s colony at Leszno long nurtured Comenius’ efforts and conviction in the awareness of its being Czech. Only the Peace of Westphalia limited the further natural development of this Bohemian Church, and its last Bishop, J.A. Comenius, wrote the Testament of the Unity of Brethren. The Polish branch of the Brethren accepted the Lutheran confession, as did the German. The restoration of the Unitas Fratrum came only in 1722; the founder of this Unity was Count Nikolaus Ludwig von Zinzendorf, who – working from Comenius’ edition of the Unity of Brethren’s statute – drew up the General Ordinance and ordained as new bishop Daniel Arnošt Jablonský, grandson of Comenius and son of Petr Figulus.
During the 18th century the Unity of Brethren expanded worldwide through missions that spread its teachings; the Unity of Brethren was restored in what was then Czechoslovakia in 1921.
The dramatic external history of the Unitas Fratrum is also matched by its dramatic internal history. The original reason for the departure of Brother Řehoř and his group was the proximity of the redemption of the soul, which is the role and aim of Man, God’s creation on Earth. If in life the priest who was meant to care for the faithful was found to have such shortcomings as roused opposition to Catholic priests, there was no certainty that such a bad priest could justly fulfil his function. The original population of Kunvald turned to the priest Matěj, in whom they trusted, and thus ensured an unbroken line of consecration. In a later period they ensured that all the feasts prescribed by the Bible and the tradition of Jan Hus and Petr Chelčický were retained. The fundamentals were later formulated in numerous apologia and defences of the faith drawn up by leaders of the Brethren to establish the differences in dogma with other Reformed, Calvinist and Lutheran faiths. The efforts of Jan Blahoslav in particular were directed at preserving the dogmatic tradition and independence of the Brethren. The priests and scholars of the Brethren devoted themselves more to working up rules of life for the faithful than to theological problems; among these rules were very strict moral requirements and the consistent exhibition of Christian love towards the world around.
The structure of the society was initially organised on the basis of the strict equality of all. Elders were elected to head the society, and from among them a narrow Council. Later, four bishops were elected. The organisational structure therefore expanded as a consequence of the joining of more and more adherents, who were accepted after a period of testing. The originally closed unit gradually became an open society that reacted to developments in the outside world, without surrendering its own identity.