Cambridge Illustrated History Germany, pg. 72
At the assembly of Nuremberg in 1356 a number of important issues were discussed, among them the question of the election of the king. It was agreed that the electors should be the archbishops of Mainz, Cologne, and Trier along with the king of Bohemia, the elector palatine, the duke of Saxony, and the margrave of Brnadenburg. Election was to be by simple majority. No mention was made of the pope's right to approve the choice. These proposals were accepted at a second Assembly in Metz and published as the Golden Bull, so named because the seal was made of gold rather than wax.
Charles IV died in 1378 leaving a power inheritance [...]
Bul|le, die; -, -n [mhd. bulle < lat. bulla, eigtl. = (Wasser)blase]:
1. Siegel[kapsel] aus Metall als Urkundensiegel bes. im Mittelalter.
2.a) mittelalterliche Urkunde mit einem Siegel aus Metall: Die Goldene B. Kaiser Karls IV.;
b) in lateinischer Sprache abgefaßter, feierlicher päpstlicher Erlaß.