20 Francs

The Kantonal-Bank von Bern was established in 1834 as one of Switzerland's earliest cantonal banks, operating during the fragmented era when individual Swiss cantons still maintained their own note-issuing privileges. That system was abolished when the Swiss National Bank was founded in 1907, which means any surviving Bernese cantonal note predates a fundamental restructuring of Swiss monetary authority by several decades.

The 1866 date places this note squarely within a period of intense political pressure on cantonal issuers — federal legislation through the 1860s was steadily tightening reserve and redemption requirements, and several smaller cantonal banks were already failing under the strain.