This chapter charts the growth of music in Wales from the late nineteenth to the late twentieth century and examines the way the infrastructure for professional music making grew, especially in the period after 1945. It examines the role played by the Welsh Arts Council (later the Arts Council of Wales), the BBC, the National Eisteddfod, the Llangollen International Eisteddfod, musical education (especially the university sector), the Guild for the Promotion of Welsh Music along with Welsh National Opera, Music Theatre Wales, and other bodies such as music clubs and festivals. The careers of composers who followed Joseph Parry, regarded as Wales’s greatest composer, are considered, including the role played by the many whose work was intertwined with the institutions that supported Welsh music. These relationships can be seen in the careers of composers such as Alun Hoddinott, William Mathias, David Harries and latterly Karl Jenkins. The chapter also considers the work of a group of composers who were important in their time but have been largely obscured by historians, including David Vaughn Thomas and Morfydd Owen. The important role they played is noted, as is the development of concert halls and other venues, such as the St David’s Hall in Cardiff and the Wales Millennium Centre.