Professor Josef Polišenský PhD. (December 16, 1915 - January 11, 2001) was an important Czech historian with a wide range of professional interest. He dedicated himself primarily to the problematics of the Thirty-Year-War and, concretely, to the Uprising of the Czech Estates in 1618 - 1620 in a broad international context. To the many histoirical problems of the Early Modern and Modern period he studied belongs also the problematics of the history of Latin America. His merits in founding the Czech Ibero-American studies were by rights appreciated abroad. The author of the article appraises the Scientific work of Professor Polišenský, from his PhD. dissertation from the year 1939, follows his professional career and his life history in the context of the ups and downs of the Czech national history, in the context of all the decoys, pressures and trials that endangered an intellectual who wasn’t indifferent to the political events. To Professor Polišenský can be given a credit for the fact that the Czech historiography in the years 1948 to 1989 was able to keep up with the European historiographical paradigms and that retained a respectable face at the same time. Unfortunately, at the moment when Polišenský found himself at the height of his Creative power, this couldn’t help him. On the contrary, it did a harm to this excellent schollar in the situation when the regime put ideological and political pressure on the science. The results of the work o f the internationally renowned scholar are and will manifest themselves also in the works of his pupils, many of them foreigners, in the activity of future generations of historians, ethnologists, archivists and specialists of other areas.