loss of the Valtellina remained an irredentist issue in Grisons well into the 20th century. Along with the Valtellina, Chiavenna was lost to the Cisalpine Republic in 1797, and the Congress of Vienna likewise declined its restoration to Switzerland. While Switzerland accepted the loss of Chiavenna itself, the Valle di Lei north of Chiavenna was indicated as Swiss territory on the Dufour map of 1858. It was only in 1863 that Switzerland reached an understanding with the Kingdom of Italy on the exact definition of the Swiss-Italian border. The Congress of Vienna distributed the remaining territory of the Prince-Bishopric of Basel (intermittently annexed by France) to Berne and Basel. The commune of Le Cerneux-Péquignot had been part the Franche-Comté and as such of the kingdom of France since 1678. It was to be ceded to Neuchâtel according to the treaty of Paris of 30 May 1814, but the necessary border correction did not become official until 1 February 1819. Similarly, Rhäzüns was restored from Austria to Switzerland on 19 January 1819. Switzerland in 1815 was still a confederacy, not a fully integrated federation. The canton of Neuchâtel joined in 1815 as a member of the confederacy but was at the same time a monarchy, its sovereign being Frederick William IV of Prussia. Although Neuchâtel became a republic in a peaceful revolution in 1848, the same year Switzerland became a federation, Frederick William renounced his claims in the area in 1857, after several attempts at counterrevolution culminating in the Neuchâtel Crisis. A number of territorial disputes remained along the German-Swiss border, especially concerning the territories of Thurgau and Schaffhausen. The status of Tägermoos was settled in 1831, the precise borders of Schaffhausen in 1839, and the final remaining questions by 1854. When Ticino chose to become part of the Swiss Confederation in 1798, the people of the Italian exclave Campione d'Italia chose to remain part of Lombardy. In 1800, Ticino proposed exchanging Indemini for Campione. In 1814 a referendum was held, but the residents of Campione were against it. In 1848, during the wars of Italian unification, Campione petitioned Switzerland for annexation, but this was rejected due to the Swiss desire to maintain neutrality. Modern Switzerland (1848–present) After Italian unification in 1861, all land west of Lake Lugano and half of the lake were given to Switzerland so that Swiss trade and transport would not have to pass through Italy. The