The flag incorporates the Red Dragon of Cadwaladr, King of Gwynedd, along with the Tudor colours of green and white. It was used by Henry VII at the Battle of Bosworth Field in 1485 after which it was carried in state to St. Paul's Cathedral. The red dragon was then included as a supporter of the Tudor royal arms to signify their Welsh descent. It was officially recognised as the Welsh national flag in 1959.
The dragon as a major flag design element is shared with the flag of Bhutan. A dragon also appears on the badge of the George Cross on the flag of Malta, and the Chinese flag also featured a dragon during the Qing Dynasty. (Several cities include a dragon in their flag design, including Cardiff, the capital city of Wales, Ljubljana, the capital city of Slovenia, and Puerto Madryn in Argentina.)