The libretto's author is unknown, but the plot is taken (like those of the Handel operas Orlando and Ariodante) from Ludovico Ariosto's Orlando furioso, an epic poem set in the time of Charlemagne's wars against Islam.
The plot of Alcina concerns the sixth and seventh cantos of Orlando furioso, which tell of a knight, Ruggiero, enslaved by the sorceress Alcina. Bradamante, Ruggiero's fiancée, and her companion Melisso rescues Ruggiero by breaking Alcina's enchantments, in the process freeing her former lovers whom she had turned into beasts, rocks, waves, and sand.
Like Handel's other works in the opera seria genre, Alcina fell into obscurity; after a revival in Brunswick in 1738 it was not performed again until a production in Leipzig in 1928.
The Australian soprano Joan Sutherland sang the role in a production by Franco Zeffirelli in which she made her debut at La Fenice in February 1960 and at the Dallas Opera in November of that year.