Přemysl Otakar II was the first of the Czech Přemyslid kings to turn his attention to Lithuania. Incidentally, Heidenreich Bishop of Chelmno from the Order of the Teutonic Knights stayed at his court; in 1253 he crowned the Lithuanian duke Mindaugas. The king came to the aid of the Teutonic Knights against the Prussians at the turn of 1254/1255 and for the second time in 1267/1268, when the eventual Christianisation of Lithuania also played an important role in his ultimately unsuccessful plans to establish a capital in Olomouc. The knightly King John of Luxembourg marched three times (1329, 1336/1337, 1344/1345) against the Lithuanians together with the Order of the Teutonic Knights and forces from western Europe. Undoubtedly of interest is the letter of Charles IV to Grand Duke Algirdas dated 21 April 1358, when he addressed him as monarcha mundi with an offer of baptism.