of the of as well as smaller parts of the of the and . Following the defeat of Napoleon at the Battle of Leipzig in 1813 and the capture of the Left Bank of the Rhine by the Allies in January 1814, from 2 February 1814 the region was initially under the provisional authority of the General Government of the Middle Rhine, but, from 16 June that same year, it was placed under the administration of the Imperial-Royal Austrian and Royal Bavarian Joint Land Administration Commission (). In the main treaty agreed at the Congress of Vienna in 1815, and dated 9 June 1815, Article 51 stated that () on the Left Bank of the Rhine the former of the and , except where stated in the same treaty, were to go "with full sovereignty" and ownership rights under the overlordship of the Emperor of Austria (). The joint Austro-Bavarian administration was initially retained, however. On 14 April 1816, a treaty was signed between Austria and Bavaria, in which the various territorial changes were agreed. According to Article 2 of the treaty, Emperor Francis I of Austria ceded various regions to Maximilian I of Bavaria. These included, in addition to various regions east of the Rhine, the following regions west of the Rhine: In the of (): the districts of , and ; the latter with the exception of the cantons of Worms and ; the canton of , in districts of . In the : the cantons of , and , the latter with the exception of several villages on the road from to , which were to be compensated, by another territorial transfer, with the agreement of the assembled plenipotentiaries of the allied powers at Frankfurt. In the of : the canton, town and fortress of , the latter as a federal fortress in accordance with the regulations of 3 November 1815; the cantons of . and the whole part of the Département of Bas-Rhin on the left bank of the , which had been ceded in the Paris Tractat of 20 November 1815. The effective date for these changes was stated as 1 May 1816. In accordance with the prevailing Bavarian administrative structure, the region was given the name "Rhine Circle" () with Speyer as its capital. Of the former French administrative structure, the subdivision of the region into cantons, mayoralties and municipalities was retained. As his