Interpolation as Critical Category Hannah Weaver (bio) Abstract Maligned by ancient Alexandrian librarians and twentieth-century philologists alike, interpolation has a long history of negative criticism that obscures its ubiquity and utility in the medieval period. This article first tells the story of criticism of interpolation, using the Latin verb interpolare as a through-line across centuries of commentary. In this vision, the consensus is that interpolations must be detected in order to be eliminated. The trouble with this story is that deleting interpolations suppresses the very idea that texts were open to such interruptive revisions; by erasing embedded texts, these editors quietly do away with an important part of medieval textual culture. To get around this problem, the article then proposes an alternative story in which medieval practices of interpolation reflect flexible attitudes toward authorship and textual unity. Drawing on Derrida's idea of the parergon, I argue for the inextricability of so-called extraneous material from the work itself. Ultimately, interpolation is revealed to be an indispensable aspect of medieval textual culture that has been unjustly sidelined because of a long history of misunderstanding it as an attack on textual integrity, rather than as a deep form of interpretive engagement. Interpolation, defined simply as nonauthorial material inserted into another text, literally and figuratively disturbs the work into which it intervenes. The embedding of foreign material reshapes the work itself. In this way, interpolation is literally disturbing. It equally troubles any certainty about the status of the textual object, figuratively disturbing those who cherish textual integrity and authorial prestige as markers of authority. Indeed, the practice is often associated with falsification and harm, particularly since sticklers insist that true interpolations attempt to fool readers by passing off the inserted material as authorial.1 A mass of ancient and medieval evidence points to interpolation as something destructive to the integrity of the text, similar to other literary "crimes" such as forgery, plagiarism, and pseudepigraphy. In his entry for the Latin verb interpolare (to interpolate), the seventeenth-century lexicographer Charles Du Cange sums up the opinion that dominated for some two thousand years when he writes, "Interpolations … are said to be additions or insertions, which in their insertion harm the books, because the originals were not copied faithfully and carefully, whether this was done on purpose or not."2 Worry over textual authority and purity of transmission exudes from this definition. Interpolation has the power to change something essential to a work––a change that Du Cange reads as invariably harmful. Perhaps because of such tenacious negative evaluations, interpolation has not received much scholarly attention to date.3 Disdainful criticism notwithstanding, interpolation was in fact a common practice in the manuscript culture of the western Middle Ages, when large-scale interpolations of dozens or even hundreds of lines appeared in works as generically diverse as histories, chivalric romances, fabliaux, lays, allegories, and the Bible, in Latin and in various vernaculars. The habit of interpolation persisted into the early print period, when pages and quires could still be added easily to books sold unbound.4 For nonspecialists, the tremendous adaptability that characterizes medieval textuality might come as a surprise, since nowadays these works are usually encountered in tidy editions that physically resemble any other large print run. Medievalists, however, have long investigated the flexibility of the [End Page 1] manuscript culture of the Middle Ages.5 Texts have been recognized as fundamentally open systems, susceptible to intervention by named and unnamed contributors. Over the last half-century, critics have described the immense mutability of medieval textualities with a suite of nonidentical but related terms, notably mouvance, variance, and "mutable stability."6 From this perspective, the amount of revisionary energy a text attracts can indicate its continuing relevance and high status, rather than lack of respect and degradation.7 Yet, although it participates in the textual flexibility characteristic of the period, medieval interpolation has not lost the shadow of critical opprobrium. Interpolation has a close kinship with many more celebrated compositional practices, including compilation, continuation, and citation, which can be performed by a number of people around the text.8 But it differs fundamentally from these in that an interpolation is always...