It describes the longing of lovers who, having passed a night together, must separate for fear of being discovered.
A common figure found in the alba is the guaita ("sentry" or "guard"), a friend who alerts the lovers when the hour has come to separate.
The following example, composed by an anonymous troubadour, describes the longing of a knight for his lady as they part company after a night of forbidden love.
While the nightingale sings, both night and day, I am with my beautiful beneath the flowers, until our sentry from the tower cries: "Lovers, get up!
The alba itself was imported into the Galician-Portuguese trovadorismo movement, but only one example of it, by Nuno Fernandes Torneol, survives.