In a famous essay, Michel Foucault introduced the term “author-function” into scholarly discourse, and later scholars of authorship in antiquity have applied the term in different ways to different concepts. Some scholars center the notion of authorship around authority, while others look to the notion of authorizing a work as a finished literary work. This article seeks to retrieve a suggestion in Foucault’s essay that the author-function can fruitfully be understood under the notion of Foucault’s French term appropriation, that is, making something belong to a person, for purposes of punishment or praise. This article applies all three notions of the author-function in scholarly use to the complex testimonium on the authorship of the Gospel of Mark by Papias in Eusebius, Church History 3.39.15, and concludes that Foucault’s own construal of his term explains best the intricacies of this ancient statement of gospel authorship.