Jacobus Yetzweirtius or Yetzweirt (born 1541) was a 16th-century nobleman who served in the Army of Flanders and wrote about the 1572 retaking of Oudenaarde.
Yetzweirtius was born in Bergues-Saint-Winoc in 1541, to a noble family of slender means. After travelling widely, he took service in the Army of Flanders as an ensign.[1] He took part in the retaking of Oudenaarde in October 1572, writing a Latin verse account of the action that was published in Ghent. Little is known of his later life.