Epistle to Cangrande

The Epistle XIII to Cangrande della Scala (Epistola XIII a Cangrande della Scala) is a letter of disputed authenticity sent by Dante Alighieri to his patron, Cangrande I della Scala.

Date
The exact date that the letter was written is unknown. The letter was cited by the Italian copyist Andrea Lancia in 1343 and then by the chronicler Filippo Villani around 1400. Some authors have suggested that Jacopo della Lana cited the letter in the 1320s, but this is disputed.

Content
The letter is divided into three parts: A dedication to Cangrande I della Scala, an accessus or introduction, and an exposition of the Divine Comedy.

Authenticity
The question of whether or not the Epistle is a forgery is controversial among Dante scholars. Scholars such as Henry Ansgar Kelly and have argued against its authenticity, whereas scholars such as, Robert Hollander, and Charles Singleton have argued that the document is authentic. Kelly specifically contends that Dante wrote the dedication but the rest of the letter was written by a "Pseudo-Dante". The academics Ralph G. Hall and Madison U. Sowell have suggested that American scholars are more likely to accept the Epistle as authentic while British and Italian scholars are more likely to consider it a forgery. John Ciardi, who wrote a translation of the Divine Comedy, argued that the framework provided by the letter is useful regardless of its authenticity. The Dante scholar Teodolinda Barolini has described the Epistle as a red herring, writing that "frankly, I don't care if the Epistle is Dante's or not, since I think the answers that I seek regarding the [Divine Comedy] are to be found in the poem itself."

In 2019, researchers for the Italian Istituto di Scienza e Tecnologie dell'Informazione attempted to use machine learning to determine authorship of the Epistle. Their results supported the theory that it was forged, however the authors noted that their study "should not be considered conclusive".