Chapter 2 explores the music produced in the monastic institutions of ninth- to eleventh-century Europe. Describing the context of the Carolingian Empire, and the renaissance of learning, literacy, and writing that it brought about, we look at some of the earliest examples of musical notation from this vast region of Europe. We examine the Latin songs, or versus, produced in monasteries, charting their wide range of themes and their possible functions in monastic life. Our earliest evidence of polyphonic singing in church comes from music theory texts dating from the ninth century onwards: we consider what these texts can tell us about the improvised practice of organum (or parallel organum) singing, and provide a practical exercise for readers to try improvising organum themselves. Further music theory texts from the tenth and eleventh centuries document the changing approaches to organum singing over the period, and finally we consider how music theory related to actual practice, by looking at the first surviving examples of practical polyphony from medieval Europe.