Elected king of the Romans in 1346 and king of Bohemia the following year, Charles IV of Luxemburg was crowned emperor at Rome in 1355 and retained the imperial title until his death in 1378. During his reign imperial policy refocused on the Germanic sphere and abandoned the ideal of the Holy Roman Empire as a universal monarchy. Charles IV concentrated his energies chiefly on the economic and intellectual development of Bohemia. He founded the university of Prague in 1348 and encouraged the early humanists ; he is known to have corresponded with Petrarch. Owing to his activity as a builder and patron, art and architecture flourished in his capital (construction of the Charles Bridge and of the Radschin, completion of Saint Vitus's cathedral by Peter Parler). From the reign of Charles IV dates the first flowering of manuscript painting in Prague. In 1356 he issued the Golden Bull which codified the procedures for imperial elections. His French education left a lasting mark on Charles IV of Luxemburg, eldest son of John of Luxemburg. The latter, known as John the Blind, king of Bohemia, was an ardent francophile and patron of the poet Guillaume de Machaut ; he died at Crécy in 1346 while fighting on the French side. Charles's sister, Bona, married the eldest son of Philip VI of Valois, the future John II the Good, in 1335. Thus, Emperor Charles IV of Luxemburg was the maternal uncle of King Charles V, who solicited his relative's advice at Metz in 1356 during the Parisian revolt. This family connection was celebrated publicly when Charles IV made a solemn visit to his nephew in 1378, just months before his death. .