Cosmas of Prague
Cosmas of Prague (c. 1045 – 1125) relates that the Přemyslid rulers of Bohemia controlled the land of Kraków until 999. In support of Cosmas, the foundation charter of the Archdiocese of Prague (1086) traces the Eastern border of the archdiocese, as established in 973, along the Bug and Styr (or Stryi) rivers. Abraham ben Jacob, who travelled in Eastern Europe in 965, remarks that Boleslaus II of Bohemia ruled the country "stretching from the city of Prague to the city of Kraków".