The early modern theatres of London were far from merely being an aspect of ‘English’ culture, as the city was gradually emerging as the centre of an empire, which encompassed Ireland. Members of Ireland’s colonial elite, as well as the increasingly affluent bourgeois, looked to London for cultural inspiration. As English power in Ireland was consolidated, cultural movement and exchange between the two cities intensified. This encouraged dialogues of politics, society and culture. From the Restoration of the monarchy in 1660 to the Act of Union in 1800, Dublin became increasingly peripheral in Britain’s expanding empire. While engaging in an Enlightenment process of ‘improvement’, Dublin increasingly modelled itself on London’s image. London’s dominant cultural position drew growing numbers of those intent upon making their name in theatre. Their departure from Ireland, however, did not necessarily signal an end to their impact on its theatres. Many returned to lead the Irish theatre scene, following the example set by London. Actors, writers and managers regularly crossed over and back between Dublin and London. Many of these pioneered influential new styles, techniques and forms, to which the canon of ‘English’ theatre is indebted. Rather than focusing on the literary or dramatic achievements of Irish individuals in London, this study will examine the wider historical significance of their cultural production. The question of Irish identity within an expanding public sphere is central to the study, most especially in analysing the opportunities and limitations that Irish theatrical personnel encountered in London and Dublin. The thesis aims to shed light on the cultural negotiation at play in the theatres, between a mentality of ‘Irishness’ and the creation of an imperial and national ‘British’ identity, as well as that of the idealized ‘Enlightened’ individual. The central objective of the project is to examine how conflicting ideas of ‘Irish’ identity were constructed, performed, and consequently shaped, by Irish actors and playwrights, both on and off the stage, while comparing the development of theatre within the public spheres of London and Dublin.