Sources: Einhard, Life of Charlemagne; the Libri Carolini; Alcuin of York’s letters; the Capitulary of Herstal (779 AD).

The Carolingian Church (~800 AD) is the institutional form of Western Christianity under Charlemagne (Charles the Great, ~742–814 AD) and his successors — the attempt to create a unified Christian civilization in Western Europe. Key developments: (1) The papal coronation (Christmas Day, 800 AD) — Pope Leo III crowned Charlemagne “Emperor of the Romans” in St. Peter’s Basilica, creating the concept of a Christian empire in the West and a complex entanglement of papal and imperial authority that would bedevil European politics for centuries; (2) The Benedictine mandate — Charlemagne required all monasteries to follow the Rule of Benedict, standardizing Western monastic life; (3) The Carolingian Renaissance — Alcuin of York directed a systematic educational reform, preserving classical texts in Carolingian minuscule script (the ancestor of modern lowercase letters); (4) The Filioque dispute — Charlemagne’s theologians inserted “and the Son” (filioque) into the Nicene Creed at the Synod of Frankfurt (794 AD) — the addition that would eventually become a primary cause of the 1054 schism; (5) Forced conversions — Charlemagne’s campaigns against the Saxons combined military conquest with mandatory baptism under pain of death, raising the perennial Christian question about the relationship between conversion and coercion. The Carolingian church model — territorial Christianity, alliance of throne and altar, clergy as administrators — dominated European Christianity for centuries.