The first official contact between Switzerland and Denmark dates back to the 17th century, when the Swiss Federal Diet, i.e. the early executive and legislative council, intervened in support of Huguenot and Piedmontese emigrants wishing to settle in Denmark.With bilateral trade relations burgeoning, Denmark opened a consulate in Bern in 1850, in St Gallen in 1854, in Geneva in 1866, then in Zurich, Basel and La Chaux-de-Fonds.
At the conference in 1864 that launched the Red Cross movement, Denmark expressed the wish for a trade agreement with Switzerland. This led to the Treaty of Friendship, Commerce and Establishment, signed in 1875.
To protect its commercial interests, Switzerland opened an honorary consulate in Copenhagen in 1887, which was transformed into a consulate general in 1921. Up to 1945, Switzerland's interests were represented by its legation in Stockholm. After being converted into a legation in 1945, the consulate general in Copenhagen was upgraded to an embassy in 1957.
In 1918, the Danish chargé d'affaires took up his post in Bern and in 1920, with the full establishment of diplomatic relations, he was accredited as minister plenipotentiary.
Denmark, Historical Dictionary of Switzerland (de, fr, it)
Diplomatic Documents of Switzerland, Dodis