Early music of the British Isles, from the earliest recorded times until the beginnings of the Baroque in the 17th century, 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 would lead to the development of English language opera at the height of the Baroque in the 18th century.
Surviving sources indicate that there was a rich and varied musical soundscape in medieval Britain. Historians usually distinguish between ecclesiastical music, designed for use in church, or in religious ceremonies, and secular music for use from royal and baronial courts, celebrations of some religious events, to public and private entertainments of the people. Our understanding of this music is limited by a lack of written sources for much of what was an oral culture.
In the early Middle Ages, ecclesiastical music was dominated by monophonic plainchant. The separate development of British Christianity from the direct influence of Rome until the 8th century, with its flourishing monastic culture, led to the development of a distinct form of liturgical Celtic chant. Although no notations of this music survive, later sources suggest distinctive melodic patterns. This was superseded, as elsewhere in Europe, from the 11th century by Gregorian chant. The version of this chant linked to the liturgy as used in the Diocese of Salisbury, the Sarum Use, first recorded from the 13th century, became dominant in England. This Sarum Chant became the model for English composers until it was supplanted at the Reformation in the mid-16th century, influencing settings for masses, hymns and Magnificats. Scottish music was highly influenced by continental developments, with figures like thirteenth-century musical theorist Simon Tailler studying in Paris, before returned to Scotland where he introduced several reforms of church music. Scottish collections of music like the thirteenth-century 'Wolfenbüttel 677', which is associated with St Andrews, contain mostly French compositions, but with some distinctive local styles. The first notations of Welsh music that survive are from the 14th century, including matins, lauds and vespers for St David's Day.