Jeûne genevois, also known as the Genevan fast or Genevan patriotic fast, is observed in the Swiss canton of Geneva every year on the Thursday following the first Sunday of September. This public holiday commemorates the St. Bartholomew’s Day massacre of 1572, which targeted French Protestants. The tradition of fasting in Geneva dates back to the 15th century, with the first canton-wide fast recorded in 1567 as a gesture of solidarity with persecuted Protestants in Lyon. Although it was declared a federal holiday in 1831, its official status was revoked in 1869, and it remained unofficial until being reinstated as a public holiday in 1966. Today, the holiday is less about religious observance and more about cultural celebration, with a popular custom of baking and enjoying plum pie (tarte aux pruneaux).