Abstrakt
Oswald Croll (ca. 1560 - 1 November 1608), a physician, alchemist, philosopher, and diplomat, was undoubtedly one of the most important European humanist scholars at the turn of the 17th century. Croll's main contribution is his laying of the foundations for the new "science"- medicinal alchemy-which he introduced in his largest published work, Basilica chymica (Frankfurt, ca. 1609).
However, his activities were not restricted solely to scientific research. One of the significant stages of his life consisted of engaging in diplomatic activities in the service of the governor of Upper Palatinate, Christian of Anhalt.
These activities led to the political unification of Protestants of the Holy Roman Empire, known as the Protestant Union. The aim of this contribution is not only to reconstruct the life of Oswald Croll, whose activities are connected with Czech political and cultural history, but also to verify the hypothesis that this particular scholar belonged to the cultural circle that gathered around Emperor Rudolf II, whose personal physician Croll allegedly became.