Los Invertidos (1914) by the Argentinean playwright José González Castillo (1885–1937) is probably the first play in the Spanish-speaking world to treat ‘sexual inversion’ – code for homosexuality in turn-of-the-century European sexology – as material for the modern stage. A three-act drama realista (‘realist drama’) that sets out to present ‘sexual inversion’ in a recognizably Argentinean setting and idiom, Los Invertidos demonstrates, as Edward Said puts it, that ‘ideas and theories’ – in this case about modern drama and sexuality – ‘travel’. González Castillo launched queer visibility on the Argentinean stage with dramatic models and embodied behaviours forged from international and local sensibilities. I argue that Los Invertidos, while shaped by sociopolitical and aesthetic upheavals in the Southern Cone, invites us to place its theatricality in a queer ‘genealogy of performance’ that crosses geographic and linguistic boundaries. How we describe and contextualize queer theatre today might well be informed by González Castillo's innovations and confusions during modern drama's early decades.