This paper aims at studying Chaucer‟s Troilus and Criseyde as an adaptation of Boccaccio‟s Il Filostrato and examining the changes that Chaucer made in his work. In this article, Il Filostrato and Troilus and Criseyde are analysed in a comparative way to understand what Chaucer wanted to suggest by making changes in the well-known story of Troilus and Criseyde. New Historicism as a literary theory, which brings together cultural, social, and historical issues in the study of a text, in addition to the poetic choices of the writer, has been applied in this study and characterization, courtly love elements and gardens as settings for courtly love are explored according to the assumptions of New Historicism