In 1309, Emperor Henry VII, Count of Luxembourg, granted imperial immediacy to the three forest cantons of Uri, Schwyz and Unterwalden. In 1843, Luxembourg joined the German Customs Union and consequently became economically linked to Switzerland.
In 1929, Switzerland signed an economic treaty with the Belgium-Luxembourg Economic Union, which had been established by Belgium and Luxembourg in 1921.
The 100th anniversary of diplomatic relations with Luxembourg was celebrated in 2017, marking the opening of a legation by the Grand Duchy of Luxembourg in Switzerland in November 1917. Up until a Swiss embassy was established in Luxembourg in 1970, the Swiss envoy in Brussels was also accredited to Luxembourg.
In 1947, Grand Duchess Charlotte and Prince Felix came to Switzerland for a state visit. In 1989, Swiss Foreign Minister René Felber made an official visit to Luxembourg. Since then, contact between the two countries has become closer and high-level diplomatic visits have been particularly frequent.
Luxembourg, Historical Dictionary of Switzerland (de, fr, it)