Frederick III of Holstein-Gottorp (22 December 1597 – 10 August 1659) was a Duke of Holstein-Gottorp.He was the elder son of Duke Johann Adolf of Holstein-Gottorp and Augusta of Denmark. His mother was a daughter of King Frederick II of Denmark.He had ambitious plans concerning the development of sea trade. With this purpose he established Friedrichstadt in 1621 in sympathy with city of Glückstadt established in 1617 by Christian IV of Denmark.
