The flag of Portugal consists of a rectangle vertically divided into green, at the hoist, and red, at the fly, with the minor version of the national coat of arms (armillary sphere and Portuguese shield) centered over the boundary between the colors. It was officially adopted on 30 June 1911, replacing the flag used under the constitutional monarchy, after it was chosen among several proposals by a special commission, whose members included Columbano Bordalo Pinheiro, João Chagas and Abel Botelho.
The current flag represents a sweeping change in the evolution of the Portuguese flag, which was always intimately associated with the royal arms. Since the country's foundation, the national flag developed from King Afonso I's blue-cross-on-white armorial square banner to the liberal monarchy's royal arms over a blue-and-white rectangle. In between, major changes associated with important political events contributed to the evolution of the national shield into its current design.