Tasso, therefore, obeyed a wise instinct when he made choice of the first crusade for his theme, and of Godfrey of Boulogne for his hero.

Having to deal with historical facts, he studied the best authorities in chronicles, ransacked such books of geography and travel as were then accessible, paid attention to topography, and sought to acquire what we now call local coloring for the details of his poem.

Without the sacrifice of truth in any important point, he contrived to give unity to the conduct of his narrative, while interweaving a number of fictitious characters and marvelous circumstances with the historical personages and actual events of the crusade.

The vital interest of the _Gerusalemme Liberata_ flows from this interpolated material, from the loves of Rinaldo and Tancredi, from the adventures of the Pagan damsels Erminia, Armida and Clorinda.

The _Gerusalemme_ is in truth a Virgilian epic, upon which a romantic poem has been engrafted.