Adam Freytag
Adam Freytag was a Polish military engineer, mathematician and physician. He is best known for his work Architectura militaris nova et aucta, the first manual of bastion fortifications of the so-called Old Dutch system, published in 1631. In 1633–1634, he served as a Polish military engineer in the Smolensk War.
Education
He graduated gymnasium in Toruń. After receiving a scholarship from the city council, he studied at the University of Frankfurt, and then moved to the Leipzig University, where he obtained a master's degree.Eighty Years' War
He joined the military of the Dutch Republic during the Eighty Years' War under the command of Frederick Henry, Prince of Orange. He took part in the Siege of 's-Hertogenbosch in 1629. From 1629 to 1632, he studied at the medical faculty of the Leiden University, obtaining a doctorate in medicine.During his stay in Leiden, he wrote Architectura militaris nova et aucta, the first manual of bastion fortifications of the so-called Old Dutch system, published in 1631. In 1632, he met future Grand Hetman of Lithuania Janusz Radziwiłł in Leiden.