During the twelfth century there were substantive changes in the nature and appearance of liturgical books. In parallel with the diversity of new texts, the twelfth century saw increased standardisation, especially through the consolidation of material previously spread across several different books into one main book for the mass and one for the divine office – the missal and breviary, respectively. The division of feasts into separate temporal and sanctoral sections became standard in this period, and large numbers of new saints’ feasts were added to the liturgical cycle. The twelfth century saw the flourishing of the versified office, in which a coherent series of chant texts was composed in verse to present the life of the saint following a formulaic pattern There were also major changes in the appearance of musical notation, with the gradual emergence of the four-line stave. Some of the most sophisticated debates over liturgical propriety took place at this time, with consequences for the presentation and content of liturgical books.