This article traces the story of one of the most significant unofficial mediators in the context of the imperial reconfiguration of the Atlantic World between the late 18th and early 19th centuries. The protagonist was a woman of many identities, loyalties, experiences, and allegiances, who stood at the center of business and family networks of global dimension. Of French descent, married to an Irishman, and naturalized a Spanish subject in Buenos Aires, “Anita” Périchon was able tostrike a balance between British and Hispanic-American imperial and personal interests. Wellknown in Argentina as the mistress of Viceroy Liniers, this article focuses on the role she played in the system of corruption that allowed British merchants to conduct business in Río de la Plata between the June 1808 alliance of Britain and anti-French Spain and the legal opening of direct trade with the British in Buenos Aires in November 1809.