Tadeáš Hájek (Thaddeus Hagecius) and Philipp Melanchthon On the basis of the Heidelberg edition of Melanchthon’s correspondence, this article examines his contacts with Prague scholar Thaddeus Hagecius – Hájek (1526–1600). The contact was initiated by a common friend, Prague humanist M. Collinus. Hájek’s name appears in the correspondence in seven places. Mutual contacts are commented on and supplemented by additional materials from Bohemia.