This article examines an unusually full set of contemporary manuscript marginalia in a copy of the 1593 edition of Sir Philip Sidney's The Countess of Pembroke's Arcadia in the Folger Shakespeare Library, most likely written by William Blount, seventh Lord Mountjoy. The marginalia demonstrate a considerable interest in the political dimension of the Arcadia, particularly in relation to Tacitus's histories, which were associated with the circle of the Earl of Essex in the 1590s. Nowhere, however, do they make an explicit connection between Sidney's work and contemporary politics. Moreover, the annotations indicate that Blount's interest in the Arcadia was by no means confined to politics and that he considered other themes independently of it. The largest group of marginalia in fact concerns ethics, and many deal with love. Blount used narrative parallels, particularly from the fourth book of Virgil's Aeneid, to explore the feelings of characters, especially women, but he was also enthused by erotic passages and included some misogynist comments. This response of a contemporary of Sidney complicates and questions recent critics’ accounts of the politics of Sidney's Arcadia and suggests an interpretation that highlights the rich variety and complexity of the work.