Portugal's national flag contains an intricate design that is both beautiful and meaningful. The colours and symbols on the flag are designed to reflect the history and progress of the nation itself.
The background of the Portuguese flag is two-fifths green and three-fifths red, with the green on the left side and the red on the remainder. The Portuguese coat of arms is centred on the line between the two colours. This symbol is made up of five blue shields in the shape of a cross, surrounded by seven castles and enclosed in a gold ring.
The original meaning of the colours on the flag is somewhat disputed, but green is generally interpreted as representing hope. The red honours the sacrifice of fallen Portuguese soldiers, specifically those who died during the revolution of 1910. The gold circle that encloses the shields is homage to Prince Henry the Navigator's original discovery of Portugal, and the castles are a symbol of the nation's expansion. The blue shields in the coat of arms and their placement represent Portugal's formation of a republic through Christianity and the victory of Count Alfonso Henriques, later King Alfonso I, over the Moors.
The symbol of the five blue shields was originally adopted by Count Alfonso Henriques after he defeated five Moorish kings in 1139. It was first used on the flag when Portugal became a republic in 1910, but did not become the official flag of the nation until 1911. The move away from the monarchy's colours of blue and white symbolised the nation's changing direction.