The flag of Glarus ultimately goes back to a banner of Saint Fridolin used in the Battle of Näfels in 1388, because the former banner of Glarus had been captured by the people of Rapperswil in a previous raid.
After this, Glarus used the image of the saint in its banners. During the 15th and 16th century, these images varied considerably. Only by the beginning 17th century a standard design was established, showing the Saint as a pilgrim in silver on a red field. The modern design shows the pilgrim in black, inspired by a banner shown in Glarus claimed as the original banner of 1388. The current official design dates to 1959.