Though its origins lie in the Middle Ages and the practices of household bards and musicians of the nobility, the modern eisteddfod tradition developed from the late eighteenth century as an essentially literary movement and part of the romantic movement that has been termed the Celtic revival. Music developed as part of the eisteddfod at local and national levels, becoming a major and eventually primary presence. The emphasis was on vocal music both solo and choral, and alongside its role in detecting and curating Welsh traditional music the eisteddfod introduced the classical concert to Welsh audiences. Eisteddfodau were always competitive events and from the later nineteenth century, choral contests helped to engender popular interest in choral singing as a practice representative of Welshness. The chapter describes the development of eisteddfodau and explains their importance in various stages of Welsh history. It also examines what were often perceived as the negative effects of eisteddfod competition and the conflict it created between meeting popular demand and the achievement of higher musical standards among the population.