In 1552, Welsh soldier and chronicler Elis Gruffydd (c.1490-c.1552) completed a 2500-folio manuscript, which is little known and rarely studied. Its obscurity belies its importance. This document can tell us much about Welsh opposition to Tudor policies in the British Isles, an often-overlooked subject; his experience as Europe transitioned from the Middle Ages to the Early Modern era; and writing as a form of resistance, a subject receiving little scholarly attention prior to the eighteenth and nineteenth centuries.