If Laski was unswerving in his opposition to heretical views, he was tolerant of other views within the Protestant camp, trying to foster unity among Reformed, Lutherans, and Polish Brethren (followers of the 15th-century reformer Jan Hus). He was also one of the translators of the first complete Polish translation of the Bible, known as the Brest Bible, or Radziwill Bible.
Jan Laski (also known as Johannes à Lasco) is normally remembered as the Reformer of Poland, but he had also a great influence in England and other parts of Europe and was an untiring opponent of the heresies of his time.
Born into a noble family in central Poland in 1499, Laski spent much of his youth at the home of their uncle, Jan Laski the Elder, archbishop of Gniezno, who oversaw his studies and directed him toward a promising career in the Catholic Church. In 1519, Laski was ordained priest and took up his ecclesiastical duties. As it often happened in those days, these duties included diplomatic relations with other countries.
He took some time away from his post in 1524 and 1525, when he traveled to France and Switzerland and became acquainted with Erasmus and other reformers. When he returned to Poland, he was appointed bishop, first in Veszprém and then in Warsaw – an indication that he was well esteemed, although his connections with Protestant reformers were already raising some rumors.
These rumors were justified, even though, in 1541, he signed a paper to confirm his allegiance to the Church of Rome. His views became finally manifest in 1543, after he moved to the Netherlands and openly repudiated the Roman Catholic teaching of transubstantiation.
By that time, he had married the daughter of a weaver, Barbara. With her, he settled in Emden, a seaport in East Frisia, on the coast of the North Sea, where he had been invited by the region’s ruler, Anna von Oldenburg, to serve as overseer of the local churches. There, he began to write religious works, an activity he continued until his death. He also continued to exchange letters with European reformers, especially the German Philip Melanchthon.