I answer the invitation to consider “medieval studies in the twenty-first century” by considering one of its mysteries in the twentieth. Thirty years ago, the work of D. W. Robertson, Jr. (who retired from Princeton in 1980 and died in 1992), polarized the field: it was the stuff of midnight debates and broken friendships; it gave his department a fearsome notoriety; it made and unmade careers. In a celebrated 1987 stocktaking, Robertson was the problem the field could not shake (Patterson 3–9, 26–39). But from this prominence, he did not dwindle; he vanished. Just as medieval literary studies steered hard into the cultural turn, he disappeared from its stage except for straw-man cameos; by 1999, The Cambridge History of Medieval English Literature could spare no breath to mention him. So who stole Robertson?