If the National Flag is a visible symbol, the National Anthem constitutes musical expression that proclaims and symbolizes the Nation.

Only after the 19th century did Europeans start using anthems, when a movement of opinion brought each state to establish a composition, with lyrics and music, that was representative and official. Until that time the people and the armies knew only the songs and martial tunes of each corps, and the songs related to events worth remembering.

During the Monarchy, the concept of the Portuguese Nation was based on the power of the king. There was no notion of a national anthem, and for this reason musical pieces with public or official character were identified with the reigning monarch.

In this context, in 1826, the Patriotic Hymn, written by Antonio Marcos Portugal, was considered a national anthem.

This anthem was inspired by the final part of the cantata La Speranza o  sia L'Augurio Felice, composed and offered to Prince-Regent Dom Joao when he was with the Court of Brazil, and which was presented at the Sao Carlos Theater in Lisbon on May 13, 1809 to celebrate his birthday.

The lyrics of the Patriotic Hymn had different versions depending on the circumstances and events of the era, naturally becoming generalized and national because of its pleasant martial expression, which rallied Portuguese spirits, inviting them to continue with heroic actions. With the return of the King to the Country, in 1821, the same author dedicated a poem to him which, when sung with the music of the Hymn, spread rapidly and came to be solemnly intoned. Meanwhile, following the revolution of 1820, on September 22, 1822, the First Liberal Portuguese Constitution was approved, sworn by D. Joao VI. D. Pedro, then Prince Regent in Brazil, composed the Imperial and Constitutional Hymn, dedicated to the Constitution.

After the death of the King, and with the rise to the throne of D. Pedro, he presented to the Portuguese a Constitutional Charter. The hymn he had written spread with the official denomination of the Hymn of the Charter, being considered officially as the National Anthem and therefore obligatory at all public ceremonies, after May 1834.

Using the music of the Hymn of the Charter, various works of public nature were composed or dedicated to important events and personalities, identifying it completely with political and social life of the last seventy years of the Monarchy in Portugal.

At the end of the 19th century, "A Portuguesa," a vibrant and stirring march, with strong patriotic sentiment, by affirming the independence it represented and the enthusiasm it drew out, became naturally and on its own merits, a national symbol.

The Hymn, meanwhile, which had been conceived to unite the Portuguese around a common sentiment, because it was sung by the revolutionaries of January 31, 1891, was downplayed by the monarchs and its performance was prohibited at official and ceremonial events.

With the installation of the Republic in 1910, "A Portuguesa" flowered spontaneously again with popular voice, being sung and played in the streets of Lisbon.

The same Constitutional Assembly of June 19, 1911 that approved the National Flag proclaimed "A Portuguesa" as the National Anthem.

This meant that the composition written by Alfred Keil and Henrique Lopes de Mendonca became official; it was an extraordinarily happy alliance of music and poetry that was able, in 1890, to successfully interpret the patriotic sentiment of revolt against the English Ultimatum, imposed in humiliating and arrogant terms against Portugal.

In 1956, there were a number of variations of the anthem, not just in its melodic line but also in the instrumentation, especially for a band. Recognizing this, the government named a commission charged with determining the official version of "A Portuguesa." This commission prepared a proposal which, approved by the Council of Ministers on July 16, 1957, remains in effect to this day.

The anthem is officially played at national civil and military ceremonies where praise is given to the Nation, the National Flag or the President of the Republic. In addition, its performance is obligatory whenever a foreign head of state is officially received on national territory the, after hearing the anthem of the represented country.