Adam Freytag (1608–1650) 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.

Adam Freytag
Memorial plaque at Freytag's childhood home in Toruń
Born1608
Died1650
Kėdainiai, Polish–Lithuanian Commonwealth