The town was founded by the Bohemian Prince Vratislav in the 10th century. In the Middle Ages it was an important trading town on the Amber Route. From 1163 the appanaged princes of Silesia had their seat here; from the 14th century onwards Wrocław lay within the lands of the Bohemian Crown, from 1742 was part of Prussia and since 1945 has been part of Poland.
In 1629 Karel the Elder of Žerotín found refuge here, bringing with him his own extensive library and the valuable Brethren library from Kralice. Comenius often worked with the books, and stayed in personal touch with Žerotín. The latter supported the Unitas Fratrum financially, and Comenius as the church’s secretary negotiated the size and purpose of the sums concerned with him. They became close not only for such administrative reasons, but more particularly because of their mutual respect and friendship.
The Brethren`s library survives today as part of the Wrocław university library.