Burgundy had been slowly falling away from the empire during its internal dissensions and its conflicts with the Papacy. But on the death of Count William IV., who was assassinated by his own people in 1127, the Emperor Lothair drew that province more closely to his realm, by bestowing the regency of it on his adherent, Conrad of Zaeringen. Conrad's position was, however, violently contested by Rainald III., a relative of the murdered count. The Burgundian nobles rallied round him, and made a desperate stand against German interference, and he maintained his independence in the Franche Comté, as the district was subsequently called. When Frederick Barbarossa married Beatrix, the daughter and heiress of Rainald, he claimed the Burgundian territory, and came into conflict with the Zaeringer. Berchtold IV. obtained the position of suzerain over the sees of Geneva, Lausanne, and Sion, and by this division Swiss Burgundy was being lopped off from its appendage beyond Mount Jura. The insubordinate prelates joined with secular princes to upset the German rule. To guard against these protracted struggles, and to increase their own influence in the country, the Zaeringer resorted to a means which does them great credit, and which won for them the affection of the people. They began to found towns, as they had done in Germany, or to raise settlements into fortified cities, and granted them extensive liberties. The lesser nobles and the common people found shelter in these walled towns against the over-bearing amongst the high nobility; trade and industry began to thrive, and these city commonwealths rose to a flourishing condition, and became a source of wealth as well as a staunch support to their founders. Bertold or Berchtold IV. (1152-1186) planned a whole strategical line of strongholds in the west, as a check on the nobles; and in 1177 he founded the free city of Freiburg on his own estates. The situation, on a high plateau above the Saane, was on the line of demarcation between the French and German tongues. To this new town he granted a charter of liberties similar to that granted to its sister foundation of the same name in the Breisgau.