George Ashby’s Active Policy of a Prince and its addendum Dicta et opiniones diversorum philosophorum, a mirror for princes written ca. 1461–1462 for the Lancastrian prince Edward, is a unique witness to the political discourse of the Wars of the Roses. As a clerk of the Signet Office, Ashby had intimate knowledge of both the inner workings of politics at the Lancastrian court as well as its key players. The Active Policy of a Prince is a largely original work of political advice written in Middle English, while the Dicta et opiniones diversorum philosophorum is a macaronic text, combining prose passages taken mostly from the Latin wisdom text Liber philosophorum moralium antiquorum, followed by Ashby’s verse translations in Middle English. This book presents a full edition of The Active Policy and Dicta with extensive glosses, notes and translations of the Latin passages.