Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Vratislaus I or Wratislaus I (Czech: Vratislav I) (c.888 February 13, 921), Duke of Bohemia (915 921), was the younger brother of Spytihnev I and the son of Bo ivoj I. By his wife Drahomira, Vratislaus had two sons, Wenceslaus and Boleslaus (also called Boleslaw I). St ezislava, the wife of the important Bohemian nobleman Slavnik (founder of Slavnik''s dynasty), is also by some historians supposed to be a daughter of Vratislaus. The Chronicle of Fulda reports that in 900 the Bavarians attacked Moravia in alliance with the Bohemians. Vratislaus died (possibly in 919, although 921 is more often conjectured) in battle against the Magyars.