Portuguese Early Music Database (PEM)

Antiphonale Synopticum
http://gregorianik.uni-regensburg.de/info

Cantus Index for Office and Mass
http://cantusindex.org

Cantus planus Regensburg
http://www.uni-regensburg.de/Fakultaeten/phil_Fak_I/Musikwissenschaft/ca...

Spanish Early Music Manuscripts Database
http://musicahispanica.eu

Cantorales (Biblioteca Nacional de España)
http://bdh.bne.es/bnesearch/Search.do?destacadas1=Cantorales&home=true&l...

CMN - Catalogue des manuscrits notés
http://www.univ-nancy2.fr/MOYENAGE/UREEF/MUSICOLOGIE/CMN/indexcmn.htm

The CMME Project: Computerized Mensural Music Editing
http://www.cmme.org

The Lugo Codex
http://opus.music.indiana.edu/s/lugocodex/index.php

DIAMM - Digital Image Archive of Medieval Music
http://www.diamm.ac.uk/

Digital Resources for Early Music
https://sites.google.com/a/haverford.edu/digital-resources/

Gallica - Bibliothèque numérique
http://gallica.bnf.fr

e-codices - Virtual Manuscript Library of Switzerland
http://www.e-codices.unifr.ch

Cantigas Medievais Galego-Portuguesas
http://cantigas.fcsh.unl.pt/

Oxford Cantigas de Santa Maria Database
http://csm.mml.ox.ac.uk/

Monophonic Chansons in Polyphonic Textures (c. 1450-1550)
http://chansonmelodies.sbg.ac.at/db/intro.php

Renaissance Liturgical Imprints: A Census (RELICS)
http://quod.lib.umich.edu/r/relics/

Center for the History of Music Theory and Literature
http://www.music.indiana.edu/chmtl/

Album interactif de paléographie médiévale
http://www.ciham.ish-lyon.cnrs.fr/paleographie/index.php

IDEM - Integrated Database for Early Music
http://idemdatabase.org/

Musicologie Médiévale - Resources for Medieval Musicology and Liturgy
http://gregorian-chant.ning.com/