Jaromír, the second son of Bohemian duke Boleslaus II the Pious and Emma of Melník, had rebelled in 1003 against his elder brother Boleslaus III, who had had him emasculated, but was unable to secure the throne, which had subsequently been taken by Boleslaw the Brave, King of Poland.

Jaromír and his brother Oldrich had then sought military backing from the German King Henry II.

At Merseburg, Jaromír had promised to hold Bohemia as a vassal of Henry, placing the country definitively within the jurisdiction of the Holy Roman Empire.

Jaromír had occupied Prague with a German army in 1004 and made himself Duke.

The state he has regained is a small one, as Polish forces still hold Moravia, Silesia, and Lusatia.

Jaromír's reign—like so many of the other early Czech rulers—has been a struggle to regain the lost lands.

On April 12, 1012, Jaromír is dethroned by Oldrich and forced once again into exile.

Oldrich recognizes the suzerainty of the Holy Roman Emperor.

According to legend, Oldrich married a woman known as Božena, daughter of Kresina, after discarding his first wife on the grounds that they were childless.