In the text of his Anglica historia of 1513, the Italian humanist Polydore Vergil did something unprecedented: he dated England’s first parliament to the year 1116 and hence to the reign of Henry I. While debate continues about the evolution of parliament, modern authorities agree that the assembly held in that year is unremarkable. As none of Vergil’s chronicle sources identified this meeting as significant, scholars have been unable to account for his reasoning. This article seeks to explain why Vergil singled out that particular assembly. It argues that the origin of parliament was an uncontroversial subject when Vergil composed his history. Over the course of the later sixteenth and early seventeenth century, writers and scholars supported and contested Vergil’s dating, but debates about the parliament’s origins cannot be associated with any particular ideological outlook.