This article considers the relationship between translation and historical alterity in Troilus and Criseyde. Chaucer opens Book II of Troilus by admitting that the customs of the poem's ancient lovers might seem strange: culture, like language, changes over the centuries. This passage probably derives from Dante's Convivio, which argues that 1,000 years of linguistic change would render the vernacular of one's own city strange and foreign. In order to understand how such alterity can emerge in a translation like Troilus, this article considers Convivio's statements in the context of fourteenth-century Italian vernacular translations that emulate the syntax and lexicon of Latin source texts. These translations expand the expressive range of the vernacular, allowing linguistic change to be glimpsed as it happens. Similarly, in Troilus Chaucer exploits the transformative potential of translation, using close translation to create effects of linguistic—and hence historical—difference within his own lexicon.