Au cours de leurs guerres civiles respectives, les chefs des partis de Bourgogne et d’York ont incarné, bien que de façon opportuniste, le désir de réforme, un courant de l’opinion publique surgi en réaction à l’essor de l’État moderne et opposé à la croissance de la fiscalité. Cet article propose une analyse comparative de leurs manifestes, naturellement voués à exposer les doléances privées et publiques. À travers l’étude des modalités de la désignation de l’ennemi public, des choix du programme politique de rechange et des paramètres temporels et géostratégiques de leur publication, les auteurs mettent en évidence la proximité des pratiques polémiques et des répertoires thématiques. During their respective civil wars, Burgundian and Yorkist leaders embodied, although in a rather opportunistic way, a desire for reform, a trend of public opinion which appeared in reaction against the rising modern state and condemned the growth of taxation. They issued various manifestoes which naturally outlined grievance private or public, and thus sparked off an abiding controversy. Our paper will focus on three main topics: 1) Those spurious texts not only targeted anonymous evil and tyrannical counselors, whose portrait they patiently painted, but they sometimes dropped names of notoriously unpopular people in power to arouse anger among their readers. The king could either be shown as a pitiable victim of his entourage or as the master of a clique of parvenus. 2) Character assassination was the first step towards an alternative political platform: polemic founded reform. The skilful depiction of an ill-treated sovereign, of an overburdened community or of a besmirched patriotism paved the way for the obvious reaction that was needed. 3) The battle-tested genre of manifesto can be declined in different variants which did not meet with the same success. We will finally consider how some issues of timing and of geo-strategy finally enabled them to achieve or miss their aim and to mobilize or simply bother the message addressees.