Romeo and Juliet
(Shakespeare). The story is taken from a poetical version by Arthur Brooke of Boisteau's novel, called Rhomeo and Julietta. Boisteau borrowed the main incidents from a story by Luigi da Porto, of Vicenza (1535), entitled La Giulietta. In many respects it resembles the Ephesiaca (in ten books) of Ephesius Xenophon, whose novel recounts the loves of Habrocomas and Anthia.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Romeo and Juliet from Fact Monster: