The trade in wine between Gascony, part of the Plantagenet-held duchy of Aquitaine (1152–1453), and the kingdom of England, emerged and evolved with a political union between the two. This thesis examines the political economy of this relationship from the Black Death (1348–9) to the end of Plantagenet rule, in order to increase our understanding of how politics interacted with the late medieval economy to influence the distribution of wealth and power within society, and vice versa. To this end this thesis asks first what English crown policies were towards the trade. Secondly it questions what the effects of these policies might have been, particularly for those political elites with vested interests in the trade in England and Gascony. Finally this thesis asks how the wine trade impacted the political relationship between England and Gascony, particularly with regards questions of loyalty to the crown. This study finds that the development of the wine market’s structure over the final century of Plantagenet rule was almost entirely dictated by the reactive requirements of contemporary politics. The crown decided the terms of merchant participation in the trade, granted commercial privileges, imposed price, exchange or export controls; and manipulated currency. Such intervention primarily resulted from pressure applied by the various interested parties: English merchants and ship-owners; as well as that of an ever-narrowing group of lords, ecclesiastics and burgesses, based in and around Bordeaux. New quantitative evidence, principally from Bordeaux’s customs books and constables’ accounts, indicates that commercial and economic benefit largely followed the pattern of political influence. In so doing English policy generated both greed and grievance, and these fed partisan conflict and rebellion in the duchy. Thus, the wine trade is demonstrated to be a key facet of the relationship between Gascony and England, and vital to our understanding its history.