What can a focus on intimacies and affinities between radical immigrants in Ireland and their Irish counterparts tell us about the transnational scope of the global Irish revolution? This article answers this question through the lives of Rose MacKenna, an Irish playwright and socialist, and her husband Sidney Arnold, a Latvian literary translator. The activist career of this obscure Irish-Latvian couple took them from revolutionary Dublin in the wake of the Easter Rising to Petrograd in the aftermath of the Russian Revolution. This article argues that MacKenna and Arnold, by virtue of their obscurity and marginality, rather than in spite of it, can suggest the sources and methodologies required to uncover the transnational world of Ireland's radical intelligentsia.