When Ninette de Valois founded a British national ballet in 1926, there was no such existing organisation. I want to re-examine de Valois’ stated claim that, after dancing with Diaghilev’s Ballets Russes, she came to understand how classical ballet was fundamental to enduring innovation in European dance, and vital to the future of British theatre. Few aspects of de Valois’ work have been subjected to deep analysis, notable exceptions being Beth Genné’s The Making of a Choreographer (1996) and Richard Cave’s monograph examining de Valois’ role in the experimental theatre of Terence Gray, and the dance-dramas of W.B. Yeats (Collaborations, 2011). Building on these investigations, I want to analyse the little understood relationship between de Valois’ radical work with Gray in Cambridge and Yeats in Dublin, and her principal occupation in London during the same period (1926–34). Here, she was establishing a ballet school and company, arguably based on an Imperial Russian/Diaghilev model. To this end, de Valois worked closely with Lilian Baylis, Manager of the Old Vic and Sadler’s Wells Theatres; the far-reaching dynamic of their partnership invites fresh investigation. Within twenty years, de Valois’ novice company became resident at the Royal Opera House (1946), the awarding of a Royal Charter (1956) confirming it as a national institution. During its rapid rise in status, the nature of de Valois’ original enterprise, and her own artistic priorities, inevitably changed. I will re-examine the formative years of The Royal Ballet and those of its founder-director through primary source archival research, and critical reassessment of the inter-war dance literature; both approaches will inform a practice-based choreographic investigation. I aim to establish what may have been lost or ‘overwritten’ of de Valois’ founding ethos and early creativeambition, and to consider the ramifications of these findings for British ballet today.