Every year colleagues introduces me to new online resources for medieval research. Some are electronic versions of old sources, some are entirely new projects. The following is my attempt to share the fruits of my colleagues' generosity with others doing research in medieval history, especially Carolingianists.
Digital Projects, INdices, and Miscellaneous resources
Orbis Latinus: Electronic version of the classic reference guide to medieval place names
Regesta Pontificum Romanorum: Searchable index of papal letters through 1198
Regesta Imperii: Index of the charters of the German emperors, including the Carolingians, and related documents
Regna Francorum Online: A "collection of hyperlinks to digitized editions of source-documents and literature concerning early medieval Europe," mostly georeferenced to its map navigation screen
Digital Atlas of Roman and Medieval Civilization (DARMC): It "makes freely available on the internet the best available materials for a Geographic Information Systems (GIS) approach to mapping and spatial analysis of the Roman and medieval worlds," though it remains a work in progress
Carolingian Canon Law Project: An impressive and expanding attempt to index, translate, and trace the Carolingian use of earlier ecclesiastical law
Hildemar Project: The important and extensive ninth-century commentary on the Rule of Benedict, now translated into English (undertaken in part by members of the Network for the Study of Late Antique and Early Medieval Monasticism)
The Electonic Sawyer: Standard index of Old English charters
Bocere.com: Links to many of the important Anglo-Saxon websites
Open Domesday: Information from the Domesday Book linked to a map and to images of the original manuscript
Regesta Pontificum Romanorum: Searchable index of papal letters through 1198
Regesta Imperii: Index of the charters of the German emperors, including the Carolingians, and related documents
Regna Francorum Online: A "collection of hyperlinks to digitized editions of source-documents and literature concerning early medieval Europe," mostly georeferenced to its map navigation screen
Digital Atlas of Roman and Medieval Civilization (DARMC): It "makes freely available on the internet the best available materials for a Geographic Information Systems (GIS) approach to mapping and spatial analysis of the Roman and medieval worlds," though it remains a work in progress
Carolingian Canon Law Project: An impressive and expanding attempt to index, translate, and trace the Carolingian use of earlier ecclesiastical law
Hildemar Project: The important and extensive ninth-century commentary on the Rule of Benedict, now translated into English (undertaken in part by members of the Network for the Study of Late Antique and Early Medieval Monasticism)
The Electonic Sawyer: Standard index of Old English charters
Bocere.com: Links to many of the important Anglo-Saxon websites
Open Domesday: Information from the Domesday Book linked to a map and to images of the original manuscript
Editions of Sources
Monumenta Germaniae Historica: Which needs no introduction, but only appreciation that it is online
Documenta Catholica Omnia: Comprehensive collection of PDF downloads of Migne (PL and PG), Mansi, Du Cange, Acta Sanctorum, and other out-of-copyright standard resources
Corpus Juris Canonici: 1582 edition
edonnelly.com Loeb Classical Library: While not medieval, a useful index of LCL volumes now out of copyright and available for download
Documenta Catholica Omnia: Comprehensive collection of PDF downloads of Migne (PL and PG), Mansi, Du Cange, Acta Sanctorum, and other out-of-copyright standard resources
Corpus Juris Canonici: 1582 edition
edonnelly.com Loeb Classical Library: While not medieval, a useful index of LCL volumes now out of copyright and available for download
Manuscript Catalogs and Digital Manuscripts
Manuscriptorium: Currently the most comprehensive website for searching for digitized manuscripts, including the German and Swiss sites below
Manuscripta Mediaevalia: Catalog of German manuscripts, including digital copies (it links into the Munich's Bayerische Staatsbibliothek, but you can go directly to the website of the Münchener Digitalisierungszentrum)
E-codices - Virtual Manuscript Library of Switzerland: The eventual goal "is to provide access to all medieval and selected early modern manuscripts of Switzerland via a virtual library"
Biblioteca Apostolica Vaticana Manoscritti digitalizzati: BAV's digital manuscripts
Catalogue of Digitized Medieval Manuscripts: UCLA's CMRS is no longer updating this resource, but it at least runs much more quickly for American users than the European sites tend to do (good for a quick look)
Telma Chartes originales antérieures à 1121 conservées en France: Includes background data as well as (often) a transcription and image of early medieval French charters
The Manuscript Transmission of Carolingian Biblical Commentaries: The most comprehensive list of known manuscripts for many Carolingian exegetes, with bibliography
Plan of Saint Gall: Digital image of the famous monastic plan and excellent commentary
The Book of Kells: Digitized by Trinity College Dublin
Manuscripta Mediaevalia: Catalog of German manuscripts, including digital copies (it links into the Munich's Bayerische Staatsbibliothek, but you can go directly to the website of the Münchener Digitalisierungszentrum)
E-codices - Virtual Manuscript Library of Switzerland: The eventual goal "is to provide access to all medieval and selected early modern manuscripts of Switzerland via a virtual library"
Biblioteca Apostolica Vaticana Manoscritti digitalizzati: BAV's digital manuscripts
Catalogue of Digitized Medieval Manuscripts: UCLA's CMRS is no longer updating this resource, but it at least runs much more quickly for American users than the European sites tend to do (good for a quick look)
Telma Chartes originales antérieures à 1121 conservées en France: Includes background data as well as (often) a transcription and image of early medieval French charters
The Manuscript Transmission of Carolingian Biblical Commentaries: The most comprehensive list of known manuscripts for many Carolingian exegetes, with bibliography
Plan of Saint Gall: Digital image of the famous monastic plan and excellent commentary
The Book of Kells: Digitized by Trinity College Dublin