Flag of the Habsburg Monarchy

Since the days of Rudolph of Habsburg and the 1283 Treaty of Rheinfelden, the combination of red-white-red was widely considered to be the Austrian (later also Inner-Austrian) colours used by the ruling Habsburg dynasty. Black and yellow later became the colours used by the Imperial House of Habsburg as they held the title of Holy Roman Emperor over centuries and were themselves derived from the banner of the Holy Roman Empire.[1] The original form of this flag featured a yellow background with a black double-headed eagle. However, this proved to be a complicated design and was hard to reproduce. In the 18th century, the simpler form with the yellow and black bars started to appear in the Habsburg Monarchy. With the end of the Holy Roman Empire in 1804, this flag was approved for use as a civil flag. The black-yellow flag was used in a way similar to a modern national flag of the Austrian Habsburg Monarchy within the Holy Roman Empire, the later Austrian Empire and the Austrian part of Austria-Hungary, sometimes still even used for the entire empire, until 1918.

Flag of the House of Habsburg

Use	Civil flag and ensign
Proportion	2:3
Adopted	18th century
Design	A horizontal bicolour of black and yellow.

Beginning in the reign of Emperor Joseph II, the Austrian, later Austro-Hungarian Navy used a Naval Ensign (Marineflagge) based on the red-white-red colours, and augmented with a shield of similar colours. Both of this and the Black-Yellow flag became obsolete with Austria-Hungary's dissolution in 1918, and the newly formed rump state of German Austria adopted the red-white-red triband as its national flag.

Today, the flag is similar to the flags of Munich, Germany; Namur, Belgium and state of Baden-Württemberg.