The national flag of Belgium contains three equal vertical bands of black (hoist side), yellow, and red; the vertical design was based on the flag of France, whereas the colours were taken from the colours of the duchy of Brabant. Its unusual proportions (13:15) are of an unknown origin.
The flag was adopted January 23 1831, soon after the Belgians gained their independence from the Netherlands in 1830. The flag had played an important role during the revolt, where the colours of the flag served as a reminder of an older flag with horizontal bands used during a previous revolt in 1789 in the then Austrian Netherlands.