|Duke of Bohemia|
|Reign||915 - 13 February 921|
|Died||13 February 921 (aged c. 33)|
|Issue||Wenceslaus I, Duke of Bohemia|
Boleslaus I, Duke of Bohemia
|Father||Bo?ivoj I, Duke of Bohemia|
|Mother||Ludmila of Bohemia|
He was a son of Duke Bo?ivoj I of Bohemia by his wife Ludmila and the younger brother of Duke Spytihn?v I. Around 906, he married Drahomíra, a Hevellian princess, to establish close ties with the Polabian Slavs. Vratislaus had at least two sons, Wenceslaus and Boleslaus, both of whom succeeded him as Bohemian dukes. Some historians believe that St?ezislava, the wife of the Bohemian nobleman Slavník, founder of the Slavník dynasty, was also the daughter of Vratislaus.
Upon the death of his elder brother Spytihn?v in 915, Vratislaus became duke at a time when the Bohemian lands around Prague Castle had already distanced themselves from the political and cultural sphere of Great Moravia and fallen under the influence of East Francia, especially during the rule of Duke Arnulf of Bavaria. The contemporary Annales Fuldenses report that already in 900 the Bavarian forces had attacked Prince Mojmir II of Moravia in alliance with the Bohemians. On the other hand, Duke Vratislaus offered the Hungarian invaders free passage and supported their 915 campaign against the Saxon duke Henry the Fowler.
Vratislaus is credited with the establishment of St. George's Basilica at Prague Castle and also with the foundation of the Silesian city of Wroc?aw (Vratislavia). He died in battle against the Hungarians, possibly in 919, although 921 is more often conjectured.