This book examines the history of a pioneering Thoroughbred horse breeding operation, the Irish National Stud. By incorporating and integrating a diverse array of primary sources from various repositories and supplementing them with contemporary and secondary materials, the main narrative reveals the intricate details of Ireland&s complex relationship with Britain through sport and politics. The publication adopts a chronological, thematic approach, beginning at the turn of the nineteenth century and tracing the development of the Stud through the twentieth century and into the twenty-first century. This book encompasses the political, cultural, and social dimensions of horse breeding/racing and the role of what would become the Irish National Stud. The first period of its history covers the establishment of Tully Stud in Kildare under Colonel William Hall-Walker in 1900. The second period, from 1916 to 1944, begins with Hall-Walker ‘gifting& Tully Stud to the British government, which then rebranded it as the ‘National Stud&. This coincided with the Irish independence struggle and the formation of the new Irish Free State, leading to over two decades of deadlock over which government-Irish or British-legally owned the Stud. The third period saw the progression of the new Irish National Stud, from its creation in 1944 to the present day, offering a comparison with the British National Stud and providing a thorough analysis of the influence of elite Thoroughbred breeders on the Irish National Stud and the broader industry in both Ireland and Great Britain.