Abstract This article examines A Commentarie or explication of a letter written by Cardinall Allen in defence of Ser William Stanleys act of Betrayinge of Deuenter , an unprinted 1587 polemical treatise by the English poet and courtier Henry Constable (1562–1613). Constable’s Catholic activities are widely documented, yet his lesser-known Protestant youth and the resulting political documents, like this treatise, have been overlooked. The tract is a detailed response to Cardinal William Allen’s A copie of a lettre , which attempted to legitimize Sir William Stanley’s high-profile defection and incite Catholic rebellion. Identified here for the first time as existing in Beinecke MS 621, the text is situated alongside Allen’s pamphlet and other contemporary Protestant responses. It showcases Constable’s staunch commitment to the English Crown and the European Protestant cause during the national crisis leading up to the Armada. His systematic refutation defends Elizabeth I’s intervention, champions the French Huguenots, and dismantles papal authority, revealing his extensive knowledge of history and the sophisticated rhetorical skills he would deploy for the rest of his life. This study offers the first physical description of the manuscript and pays attention to the authorial revisions, which reflect Constable’s acute awareness of the rapid political decline of his patron, Robert Dudley, Earl of Leicester. The treatise is a unique textual artifact and an invaluable record of Constable’s shrewd navigation of political necessity, providing essential context for his later diplomatic career.
María Jesús Pérez-Jáuregui (Sat,) studied this question.