In his Defence of Poetry (c. 1580), Philip Sidney argues that poetry—a category in which he includes all imaginative fiction—aims at the education of its readers. Archepollycyes studies the attempts of a loose group of sixteenth-century writers around Sidney to write fiction that lives up to this aim, in order to understand the methods they developed to educate readers and the relationship between this education and the politics of the monarchical state. Sidnean fiction demands long study on the part of its readers because it aims to transform their mental habits and create new internal resources for right action. The works of fiction I study here—Thomas Sackville and Thomas Norton’s Gorboduc, George Buchanan’s Baptistes, Sidney’s Arcadia, Mary Sidney Herbert’s Antonius and A Discourse of Life and Death, and Fulke Greville’s Mustapha—were products of their authors’ experiments with genre, narrative, translation, and style as tools to achieve this aim. Through the reading experience these works invite, readers exercise their judgment in the interpretation of fictional examples and reflect explicitly on the mental habits of generalization and application that inform decisions about how to act in new circumstances. Readers also come to see these habits of judgment as shared with others and experience the act of reading as participation in both real and imagined interpretive communities. I argue that these interpretive communities are best understood as loose political institutions, networks of organization and affiliation whose members could think and act together through common habits of judgment and the mutual resolution that results from recognizing this commonality. I adopt the term “archepollycyes” from Gabriel Harvey in order to describe the role of such institutions in monarchical politics. Harvey coins the term to describe the foundational forms of political knowledge, action, and organization, in contrast to the day-to-day work of government and the business of political rule. “Archepollycyes” hold a political community together in spite of changes in its ruler or government; understanding and creating such institutions was thus a means of responding to the escalating crises of succession, absolutism, and civil war that confronted early modern monarchies. By reading and writing fiction, I argue, Sidney and a broader network of writers aimed to act at a distance from contemporary political conflicts by founding “archepollycyes,” loose institutions capable of acting independent of the monarchical state and outside of existing structures of government, but on behalf of the long-term stability of a political community. In this way, I offer a new way of thinking about fiction and political institution in relation to the contested emergence of the modern sovereign state.