Portuguese has a word, saudade. Dictionaries reach for "longing," "nostalgia," "yearning," and every one of them lands only halfway. It is the ache for something lost, braided together with a strange tenderness toward the very fact of having lost it. It is waiting for what you know will never return, and somehow loving the waiting. The Portuguese have used this one word for centuries to name that contradictory state of the heart.

Fado is what happens when saudade is set to music. The name comes from the Latin fatum, meaning fate, and true to its name, fado sings of a destiny you cannot argue with. It is said to have emerged in the first half of the 19th century in Lisbon, in the back alleys of Alfama and Mouraria, the poor waterfront districts, among sailors, prostitutes, and the destitute. A twelve-stringed Portuguese guitar shivers in quick tremolos, and over it a single voice wrings out its losses: a vanished love, a distant sea, a person who never came home.

Portugal was a nation that lived by the sea. In the age of discovery, men set sail from this small country toward the ends of the earth, and many never returned. The feelings that piled up in the chests of those left waiting at the harbor became the very foundation of fado. That is why the music is always, at its core, passive. It does not try to change the world. It only gives a name to the pain of living inside a world that cannot be changed. For a long time, fado was supposed to be exactly that, and nothing more: a song of consolation, innocent of politics.

The person who lifted fado out of the gutter alleys and into national art was Amália Rodrigues. Born in 1920 into a poor Lisbon family, a girl who sang while selling fruit, she would become the defining Portuguese voice of the 20th century. When she sang, an ordinary lyric about heartbreak could sound like the lament of a whole human life. Through her, fado became known worldwide, until in Paris, Rio, or Tokyo, the word "Portugal" would summon the sound of Amália's voice.

But the era in which she shone was also a dark one for her country. From 1933 to 1974, Portugal lived under a dictatorship called the Estado Novo, the "New State," led by António Salazar (and, from 1968, by his successor Marcelo Caetano). Speech was censored, a secret police watched over citizens, and in the African colonies wars of independence dragged on. Critics later joked that the regime kept the population docile with what they called the "three Fs": Fado, Fátima (the Catholic pilgrimage site), and Futebol (football). As long as people were singing, praying, and kicking a ball, the reasoning went, they would forget about politics.

So the passive character of fado, its insistence that fate cannot be resisted, suited the dictatorship perfectly. A song that mourned the present without ever trying to change it. A song of resignation rather than revolt. And so fado, regardless of what the people who loved it actually felt, came to be seen as music that stood on the side of the regime. Amália herself was no political singer, and it later emerged that she had quietly given financial support to the opposition, but her voice was simply too national, and it was pressed into service as one of the faces of the state. The track below is her signature song, "Barco Negro" (Black Boat). Set to a melody of Brazilian origin, it is the song of a woman trying to believe that her dead lover is still out there beyond the waves. That beauty, refusing to fight against fate, was fado itself.

Right beside a fado that accepted its fate, there were people who began singing the exact opposite. In the 1960s, centered on the students of Coimbra University, a movement grew of what was called canção de intervenção, the "intervention song": music written to change society. Armed with a single guitar and an arsenal of metaphor to slip past the censors, they sang of freedom, of equality, of brotherhood. At the heart of it stood José Afonso, who was also a schoolteacher.

The song he released in 1971, "Grândola, Vila Morena," sounds at first like a plain, gentle tribute to a small country town. But read the lyrics closely and you find a message that was extraordinarily dangerous under a dictatorship: that the town is governed by its people, and that every man is an equal brother. Predictably, the song was banned from the airwaves.

And then, on April 25, 1974, this banned song became the signal that moved history. Young military officers, no longer able to bear the colonial wars and the dictatorship, had planned a bloodless coup. The cue to rise up was to come over the radio in two stages. First, at 10:55 p.m. the night before, Paulo de Carvalho's "E Depois do Adeus" aired as the first signal, telling the units that the operation was on. Then, at 12:20 a.m. on April 25, a station broadcast "Grândola, Vila Morena" as the second signal — the order to move. Units across the country, hearing it, began to move in unison, and by the end of that day the Estado Novo had collapsed, almost without a shot being fired. Citizens slipped carnations into the barrels of the soldiers' rifles, and so the uprising came to be called the Carnation Revolution.

A country that passive fado had soothed for forty years was woken in a single night by one forbidden song. It was the moment a song became not a comfort, but a trigger for action.

Ironically, in the immediate aftermath of the revolution, fado found itself in a difficult position. Because it had been seen as the regime's music, a newly free Portugal briefly shunned it as a lingering scent of the dictatorship. A song that accepts its fate was, for a while, too heavy for a country that had just seized its fate with its own hands.

But that did not last long. Fado was gradually pried loose from politics and heard again for what it had always been: the music of one heart at a time. In the 2000s, a new generation, including Mariza, who was born in Mozambique, sang fado with a contemporary sensibility while keeping its traditional shape, and pushed it back onto the world-music stage. The track below is Mariza's "Ó Gente da Minha Terra" (O People of My Land), a fado about what fado is, showing how the fate of the back alleys can still resonate in the 21st century. In 2011, UNESCO inscribed fado on its list of Intangible Cultural Heritage.

And saudade was never Portugal's alone. On Cape Verde, the Atlantic islands once linked to the mainland by the same ships, there is a song called morna, a blood relative of fado. "Sodade," sung by Cesária Évora, the "barefoot diva," is exactly what its title says: the ache of an emigrant longing for a homeland left far behind. This feeling, shared across the Portuguese-speaking world, has been carried across ocean after ocean, changing its shape a little in each place it landed.

A song of comfort, and a song that became a weapon. One small country, in one span of years, gave birth to both. A voice that accepts its fate, and a voice that stands against it. Portuguese music still holds out these two utterly different answers, side by side, to the question of how a person should face their pain.