Louis I, Emperor, 778-840 (Personal Name)
- Earlier heading: Louis I, le Pieux, Emperor, King of the Franks, 778-840
- Louis I, Emperor of the Franks, 778-840
- Hludowic I, Emperor of the Franks, 778-840
- Ludwig I, Emperor of the Franks, 778-840
- Louis, the Pious, 778-840
- Ludwig, der Fromme, 778-840
- Louis, le Pieux, 778-840
Studien zu den Gesta Hludowici Imperatoris ... 1988: p. v (Ludwig, der Fromme)
Acad. Amer. enc. (Louis I, Frankish Emperor; Louis the Pious, b. 778, d. 6-20-840)
Enc. Amer., 1988 (Louis I, 778-840, Frankish emperor; last ruler of united Carolingian empire, succeeded Charlemagne)
Enc. Brit., 15th ed. (Louis I the Pious, Emperor)
LC in RLIN, 7-18-89 (hdg.: Louis I, le Pieux, Emperor, King of the Franks, 778-840)
New Cath. enc. (Louis I, the Pious, German emperor)
Dict. Middle Ages (under Holy Roman Empire: Carolingians employed the title "Emperor" without reference to a particular territorial entity)