Brill Encyclopedia of Early Christianity (Online). Ed. David G. Hunter, Paul J. J. van Geest, & Bert Jan Lietaert Peerbolte. 6 vols. projected. 2018- .
Encyclopedic dictionary of the Christian East, 2nd ed., rev. & expanded by 
Encyclopedia of Ancient Christianity. Ed. Di Berardino. 3 vols.
Encyclopedia of Early Christianity. 2nd ed. Ed. Ferguson. 2 vols.
Encyclopedia of the Early Church. Ed. Di Berardino. 2 vols.
Westminster Handbook to Patristic Theology. McGuckin.
Augustine through the Ages: an Encyclopedia. Ed. Fitzgerald.
Brill Dictionary of Gregory of Nyssa. Ed. Mateo-Seco & Maspero.
Westminster Handbook to Origen. McGuckin.
Brill's Encyclopedia of the Middle Ages. Ed. Melville & Staub. 2 vols.
Oxford Dictionary of the Middle Ages. Ed. Bjork. 4 vols.
Encyclopedia of the Middle Ages. Ed. Vauchez. 2 vols.
Dictionary of the Middle Ages. Ed. Strayer. 13 vols. + Suppl.
Medieval England. Ed. Szarmach, Tavormina, & Rosenthal.
Medieval Germany: an Encyclopedia. Ed. Jeep.
Medieval Iberia: an Encyclopedia. Ed. Gerli.
Medieval Ireland: an Encyclopedia. Ed. Duffy.
Medieval Italy: an Encyclopedia. Ed. Kleinhenz.
Medieval Scandinavia: an Encyclopedia. Ed. Pulsiano.
Key Figures in Medieval Europe: an Encyclopedia. Ed. Emmerson.
Medieval Science, Technology, and Medicine: an Encyclopedia. Ed. Glick, Livesy, & Wallis.
Trade, Travel, and Exploration in the Middle Ages: an Encyclopedia. Ed. Friedman & Figg.
Women and Gender in Medieval Europe: an Encyclopedia. Ed. Schaus.
Companion to Philosophy in the Middle Ages. Ed. Gracia & Noone.
The Encyclopedia of Medieval Literature in Britain by 
Encyclopedia of Medieval Pilgrimage. Ed. Taylor et al.
Westminster Handbook to Medieval Theology. Ginther.
Westminster Handbook to Thomas Aquinas. Wawrykow.
Canterbury Dictionary of Hymnology
Oxford Dictionary of the Christian Church. 4th ed. Ed. Louth. 2 vols.
New Catholic Encyclopedia. 2nd ed. Ed. Marthaler. 15 vols. + suppls.
Encyclopedia of Christianity. Ed. Fahlbusch et al. 5 vols.
Religion Past and Present. Ed. Betz et al. 13 vols.
New Westminster Dictionary of Church History. Ed. Benedetto. Vol. 1: The Early, Medieval, and Reformation Eras
A Dictionary of Asian Christianity. Ed. Sunquist.
Oxford Dictionary of Byzantium. Ed. Kazhdan. 3 vols.
Coptic Encyclopedia. Ed. Atiya. 8 vols.
Blackwell Dictionary of Eastern Christianity. Ed. Parry et al.
Encyclopedia of Eastern Orthodox Christianity. Ed. McGuckin. 2 vols.
Encyclopaedia Aethiopica. Ed. Uhlig & Bausi. 5 vols.
Encyclopædia Iranica. Ed. Yārshāṭir. 16 vols. to date.
Encyclopedia of Monasticism. 2 vols. by 
Encyclopedia of Christianity in the Global South by 
Oxford Encyclopedia of South Asian Christianity. Ed. Hedlund. 2 vols.
Encyclopedic Dictionary of the Syriac Heritage. Ed. Brock et al.
Papacy: an Encyclopedia. Ed. Levillain. 3 vols.
Dictionary of Popes and the Papacy. Ed. Steimer & Parker.
Augustinus-Lexikon. Ed. Mayer. 4+ vols. to date.
The Oxford Dictionary of Late Antiquity. 2 vols. by 
Late Antiquity: A Guide to the Postclassical World by 
Critical Dictionary of Apocalypic and Millenarian Movements (CDAMM)
Encyclopedia of Apocalypticism. Ed. Collins, McGinn, & Stein. 3 vols.
Encyclopedia of Millennialism and Millennial Movements by 
Eeerdmans Encyclopedia of Early Christian Art and Archaeology. Ed. Finney. 3 vols.
Reallexikon zur deutschen Kunstgeschichte. 1937- .
