Not many reports have survived which capture the pre-exile activity of Jan Amos Comenius, and his personal life in particular. A signifi cant number of them consist of brief retrospective communications preserved in some of Comenius's literary works and in his correspondence. The actual sources from the pre-White Mountain period make possible only a rough reconstruction of the basic milestones in his life, often only hypothetical (the question of his birthplace can be mentioned as an example). Somewhat more light is shed on this period by material from the Archive of Matouš Konečný, discovered in Mladá Boleslav in the summer of 2006. Included in it are letters from Jan Lanecký († 1626) to the Bishop of Mladá Boleslav, who was, between 1609–1620/1622, Matouš Konečný. As Bishop of the Přerov diocese, Lanecký was Comenius's immediate superior and at the same time his closest guide on the path to his priestly profession. An indivisible part of this process was the, at least partial, absolving of the theological study for which the novices of the Brethren's priesthood were sent to educational institutions abroad. Lanecký's letters supplement in interesting details the background to Comenius's stay in Herborn and Heidelberg, starting with the late departure of the Brethren students from Moravia and Bohemia because of the invasion of the Passau soldiers (1611). The letters capture in a very rounded way the chronic problems the students had with the fi nancial demands of the study, culminating in the indebtedness of several individuals, which became a heavy burden to them after their return to their native land. The letters also document the tension arising from the diff ering ideas of the students and the bishops about the content of the study itself, and its form. They provide valuable evidence for the motives of Comenius's journeys and his pleasure in the travel the students enjoyed in their free time. A number of new pieces of information relate to Comenius's activity in Moravia after 1614. Especially valuable are reports about Comenius's ordination as a deacon, which took place on 2 February 1616 in Prague, as well as Lanecký's communications about Comenius's literary beginnings: for example, clarifi cation about the authorship of the work Retuňk proti Antikristu [Warnings Against the Antichrist], and the reaction of the Brethren bishops to the origin of the work Theatrum universitatis rerum. Among the interesting matters which the new information about Comenius opportunely supplements are reports of two letters from the Ivančice Bishop Jiří Erast (from 1616 and 1618). They are evidence of a Brethren priest called Komenský, who was working in the Ivančice diocese in the time before the Uprising of the Bohemian Estates broke out. However, we know nothing more about his life or possible relationship to Jan Amos Comenius.