The beautiful flag of the nation of Portugal has undergone numerous changes over the centuries. The current Portuguese flag represents a fusion of Medieval heraldic symbolism and ideas underlying modern constitutional government.
Portugal’s unique geography and maritime traditions have influenced its flag in significant ways, too. This nation of slightly over ten and a half million people occupies a narrow strip along the western coast of the Spanish Peninsula and several Atlantic Islands. It maintains a long Atlantic coastline and has been heavily influenced over the years by the culture of its only immediate adjoining nation, Spain.
The Romans conquered Portugal in 140 B.C. For centuries, this region formed part of the Roman Empire. Nomadic Germanic tribes invaded when the Roman Empire fell. Later, in 711, a Muslim invasion of the Spanish Peninsula from North Africa resulted in the establishment of several Islamic Moorish principalities. Northern Portugal remained an embattled Christian kingdom. During much of the next four hundred years, the history of Portugal was dominated by warfare between Christian and Moorish factions. Modern Portugal’s border within the Spanish Peninsular arose in 1270 when Catholic King Afonso III gained firm control. At that time, the flag of Portugal reflected his heraldic banner of a shield displaying five blue castles arranged in the shape of Catholic Cross and surrounded by a thick red border displaying golden castles.
The Portugal flag changed numerous times during the Middle Ages and Renaissance Period, when a monarchy ruled Portugal. The ruler’s heraldic crest continued to carry the five blue castles in a cross formation arrayed on a white shield, but sometimes included other symbols, too. The number of golden castles along the shield’s red border changed from time to time. The Portugal flag for most of this period displayed a white field, with the royal crest placed in the center. The monarchy began using a golden spherical navigational instrument encircling its crest and a white and blue field as Portugal expanded its maritime activities to distant regions.
When the monarchy fell from power following political upheaval early in the Twentieth Century, the background of the Portuguese flag changed from white and blue to 2/5 green on the hoist side and 3/5 scarlet on the fly side. It still carried the national heraldic crest. Portugal officially adopted this flag on June 30, 1911 to recognize the shift in power to a secular government.