Less than fifty years later, the Kyburgs died out, and large portions of their domains were inherited by the House of Habsburg. Bern achieved the status of a free imperial city, whereas other cities (such as Fribourg-Freiburg) only obtained the same status later in history. Possessions and territories Berthold I (ancestor of both the House of Zähringen and the House of Baden) held the comital titles of Breisgau and Thurgau, as well as being reeve in Stein am Rhein (owned by the bishop of Bamberg). The county of Thurgau was lost around 1077. In 1098, Berthold II, founder of the House of Zähringen proper, received Zähringen Castle and the jurisdiction over Zürich (alongside the Counts of Lenzburg until 1173). Ownership of the county of Rheinfelden and of Burgdorf also dates to c. 1198. The 'rectorate' of the county of Burgundy was granted in 1127 (inheritance of Otto-William, Count of Burgundy). Ownership of Burgundy was contested, and Zähringer de facto rule was limited to the parts of Upper Burgundy east of the Jura and north of Lake Geneva. The territories south of Lake Geneva were conceded to Savoy and Provence in 1156. In compensation, Berthold IV received the investiture right for the bishops of Geneva, Sion and Lausanne, de facto realised only in the case of Lausanne. The extinction of the counts of Lenzburg in 1173 strengthened the Zähringer position south of the Rhine, but their territorial expansion was halted following their support of the Welfs in the unsuccessful feud against Conrad III of Germany during 1138–1152. This frustrated their ambitions to carve out a contiguous territorial duchy wedged between Swabia and Burgundy, in spite of late attempts on the part of Berthold V to increase his territorial sway (who as late as 1210 aimed at receiving the jurisdiction over St. Gallen). Instead of territorial expansion, the dukes of Zähringen from the 1150s focussed on attaining more immediate feudal control over the territories they already had. This included their policy of expanding settlements into fortified towns or cities and the construction of new castles, mostly in their territories north of the Rhine. Their encroachment on the rights of the comital nobility south of the Rhine seems to have been resisted, mostly passively, but in the case of the lords of Glâne and Thun in an open revolt in 1191. The fragmentation of the Zähringer possessions after 1218 was an important factor