Johann von Geyso

Johann von Geyso (1593 – 1661) was a German nobleman and General-Lieutenant, who fought during the course of the Thirty Years' War. After studying in a Dutch military academy, Geyso fought as a mercenary in the armies of Sweden, Bohemia, Denmark and the German Protestant Union. In 1628, having gained significant experience in warfare he returned to his native Hesse-Kassel which he served until the end of the Thirty Years' War, reaching the rank of commander in chief of the Langraviate's forces and becoming ennobled.