De vulgari eloquentia
De vulgari eloquentia (Ecclesiastical Latin: [de vulˈɡari eloˈkwentsi.a], Italian: [de vulˈɡaːri eloˈkwɛntsja]; "On eloquence in the vernacular") is the title of a Latin essay by Dante Alighieri. Although meant to consist of four books, it abruptly terminates in the middle of the second book.