Yeats was an important – if sometimes ambivalent – early supporter of O’Casey. As co-director of the Abbey, Yeats played an important part in first getting O’Casey’s Dublin writing to the stage and in defending that work from critics. Yet, although the Abbey had fostered O’Casey’s talents, W. B. Yeats led his fellow directions in rejecting O’Casey’s 1928 work The Silver Tassie in a way that had a major impact both upon O’Casey’s career and upon the Abbey Theatre’s own history. This chapter interrogates the relationship between O’Casey and Yeats, which is inextricably bound to central tensions at the heart of the early years of the Abbey Theatre.