The current National Anthem of Portugal was composed in record time right before the Portuguese revolt of January 31st, 1891, by Alfredo Keil and lyrics by Henrique Lopes de Mendonça.
Today, it is one of Portugal’s national symbols. The song itself was born as a patriotic song in response to the British ultimatum to abandon the Portuguese positions in Africa. The territory in question was the area between the colonies of Mozambique and Angola, included in the famous “Pink Map”. More info here on the Portuguese pink map.
The video below is me singing the first verse of the anthem. The full lyrics are further below.
Below is a video history lesson about how Portugal became a republic.