As the use of English in worship services spread, the need for a complete uniform liturgy for the Church became evident. Initial meetings to start what would eventually become the 1549 "Book of Common Prayer" were held in the former abbey of Chertsey and in Windsor Castle in September 1548. The list of participants can only be partially reconstructed, but it is known that the members were balanced between conservatives and reformers. These meetings were followed by a debate on the Eucharist in the House of Lords which took place between 14 and 19 December. Cranmer publicly revealed in this debate that he had abandoned the doctrine of the corporeal real presence and believed that the Eucharistic presence was only spiritual. Parliament backed the publication of the Prayer Book after Christmas by passing the Act of Uniformity 1549; it then legalized clerical marriage.