After in 1310 the Bohemian crown had passed to the mighty House of Luxembourg, nearly all Silesian dukes pledged allegiance to King John the Blind and in 1335 the Polish king Casimir III the Great officially renounced Silesia by the Treaty of Trentschin. King John had also acquired the lands of Bautzen and Görlitz (later Upper Lusatia) in 1319 and 1329. His son and successor Charles IV, also King of the Romans since 1346, incorporated the Silesian and Lusatian estates into the Bohemian Crown and upon his coronation as Holy Roman Emperor confirmed their indivisibility and affiliation with the Holy Roman Empire.