Duchy of Courland and Semigallia (1561−1795)

The state flag of the Duchy of Courland and Semigallia (1561−1795) was a long rectangle with aspect ratio of 1:2. It was divided into equal horizontal stripes, red on top, and white on the bottom.^[1][2] The civil ensign also utilised the 1:2 ratio. It was divided into two square parts. The left part consisted of 4 red and white squares placed in the checkerboard pattern, with red squares being at the top left and bottom right, while the white squares being at the top right and bottom left. The right side consisted of two equally derived horizontal lines, red at the top, and right at the bottom.^[2]

During the reign of duke Jacob Kettler, which lasted from 1642 to 1682, the naval ensign used by the ships used during the Courlanian colonization of West Africa and Caribbean, was a raspberry red with a crab on it.^[3] The version with a black eagle instead of a crab was also used.^[4]

There were also two other flags used by the state: a red flag with a white eagle, and a white flag with a black eagle.^[3]

Courland Governorate (1795–1918)

The flag used by the Courland Governorate (1795–1918), within the Russian Empire, was a rectangle divided into three equal stripes: green at the top, blue in centre, and white at the bottom.^[5]