Flag of Switzerland dates to 1540, in the context of an auxiliary force sent by the Swiss to aid their associate, the city of Rottweil, in a feud against the lords of Landenberg. The "Tagsatzung" decided that the Swiss auxiliaries sent to Rottweil should receive "a red flag with a white upright cross". The first mention of the term "Confederate Cross" ("Eidgenossen Crütz") dates to 1533. Because of the Swiss pledge of neutrality, there was no military conflict in which the Swiss confederate troops participated after 1540. Consequently, the confederate field sign fell out of use. At the same time, the former field
Flag of Switzerland squares until 1889, when its dimensions were officially set. The civil and state ensign of Switzerland, used by Swiss ships, boats and non-governmental bodies, is rectangular in shape and has the more common proportions of 3:2. The Swiss flag is one of only two square sovereign-state flags, the other being the flag of Vatican City. The emblem of the Red Cross is the Swiss flag with switched colours. According to the 2017 flag law (SR 232.21), "The Swiss flag shows a Swiss cross on a square background". Special provisions are made for the naval ensign and for civil aircraft identification.