The tenth and early eleventh centuries often fall between the cracks of the “Carolingian Renaissance” and the “Gregorian Reform” of the eleventh-century papal reform movements. Yet scholars are now paying closer attention to the “long tenth century,” c. 900–1020/50. This new research has undermined the idea that Church law sank into a dark period. Canon law, in fact, may be more difficult to describe in this time than in later periods, precisely because it took place on a “horizontal” level, with many local users, rather than unified under a “vertical” papal monarch, as it would be later. Church law was pluralistic in many senses. Many people used it: the local priest; abbots and monks; the bishop, both in teaching and in administering episcopal courts; and councils, sometimes with popes and emperors present. The remarkable number of canon law manuscripts from this period attests to the considerable local interest in canon law. Collections of Church law from this period also continued to be copied into the high Middle Ages – which also testifies to the significance of the achievements of this period. Viewed diachronically, Church law in this period built upon Carolingian legislation as well as institutions and structures.