dynasty, died out and they could thus bring much of the territory south of the Rhine under their control. Subsequently, they managed within only a few generations to extend their influence through Swabia in south-eastern Germany to Austria. Under the Hohenstaufen rule, the alpine passes in Raetia and the St. Gotthard Pass gained importance. Especially the latter became an important direct route through the mountains. The construction of the "Devil’s Bridge" () across the in 1198 led to a marked increase in traffic on the mule track over the pass. Frederick II accorded the Reichsfreiheit to Schwyz in 1240 in the Freibrief von Faenza in an attempt to place the important pass under his direct control, and his son and for some time co-regent Henry VII had already given the same privileges to the valley of Uri in 1231 (the ). Unterwalden was reichsfrei, since most of its territory belonged to monasteries, which had become independent even earlier in 1173 under Frederick I "Barbarossa" and in 1213 under Frederick II. The city of Zürich became reichsfrei in 1218. While some of the "Forest Communities" (Waldstätten, i.e. Uri, Schwyz, and Unterwalden) were reichsfrei the Habsburgs still claimed authority over some villages and much of the surrounding land. While Schwyz was reichsfrei in 1240, the castle of Neu Habsburg was built in 1244 to help control Lake Lucerne and restrict the neighboring Forest Communities. In 1245 Frederick II was excommunicated by Pope Innocent IV at the Council of Lyon. When the Habsburgs took the side of the pope, some of the Forest Communities took Frederick's side. At this time the castle of Neu Habsburg was attacked and damaged. When Frederick failed against the Pope, those who had taken his side were threatened with excommunication and the Habsburgs gained additional power. In 1273 the rights to the Forest Communities were sold by a cadet branch of the Habsburgs to the head of the family, Rudolf I. A few months later he became King of the Romans, a title that would become Holy Roman Emperor. Rudolph was therefore the ruler of all the reichsfrei communities as well as the lands that he ruled as a Habsburg. He instituted a strict rule in his homelands and raised the taxes tremendously to finance wars and further territorial acquisitions. As king, he finally had also become the direct liege lord of the Forest Communities, which thus saw