Classical music of the United Kingdom is taken in this article to mean classical music in the sense elsewhere defined, of formally composed and written music of chamber, concert and church type as distinct from popular, traditional, or folk music. The term in this sense emerged in the early 19th century, not long after the United Kingdom of Great Britain and Ireland came into existence in 1801. Composed music in these islands can be traced in musical notation back to the 13th century, with earlier origins. It has never existed in isolation from European music, but has often developed in distinctively insular ways within an international framework. Inheriting the European classical forms of the 18th century (above all, in Britain, from the example of Handel), patronage and the academy and university establishment of musical performance and training in the United Kingdom during the 19th century saw a great expansion. Similar developments occurred in the other expanding states of Europe (including Russia) and their empires. Within this international growth the traditions of composition and performance centred in the United Kingdom, including the various cultural strands drawn from its different provinces, have continued to evolve in distinctive ways through the work of many famous composers.
Music in the British Isles, from the earliest recorded times until the Baroque and the rise of recognisably modern classical music, was a diverse and rich culture, including sacred and secular music and ranging from the popular to the elite. Each of the major nations of England, Ireland, Scotland and Wales retained unique forms of music and of instrumentation, but British music was highly influenced by continental developments, while British composers made an important contribution to many of the major movements in early music in Europe, including the polyphony of the Ars Nova and laid some of the foundations of later national and international classical music. Musicians from the British Isles also developed some distinctive forms of music, including Celtic chant, the Contenance Angloise, the rota, polyphonic votive antiphons and the carol in the medieval era and English madrigals, lute ayres and masques in the Renaissance era, which led particularly to English language opera developed in the early Baroque period. The dominant figure in classical music in the later baroque era, and beyond, was the German-born George Frideric Handel (1685–1759).