Kingdom of Atlantia Arts and Sciences Links
http://moas.atlantia.sca.org/
An excellent source for links on a wide selection of A&S topics
Elizabethan Costume Page
http://www.elizabethancostume.net/
Drea Leed's site about all things Elizabethan
Regia Anglorum's Articles
https://regia.org/
A source for articles about Anglo-Saxon Britain
CELT: The Corpus of Electronic Texts
http://www.ucc.ie/celt/
A collection of Irish texts online.
Archaeology Data Service
https://archaeologydataservice.ac.uk/archive/
Free online access to a number of archaeology journals.
Early Manuscripts at Oxford University
http://image.ox.ac.uk/
Images of many of the early manuscript in many of Oxford's University libraries.
ORB - Online Reference Book for Medieval Studies
https://the-orb.arlima.net/
Searchable Primary Texts, including Anglo-Saxon Chronicle, Bede, links to much more
Internet Medieval Sourcebook
http://www.fordham.edu/halsall/sbook2.html
Online full text medieval documents
EuroDocs
http://eudocs.lib.byu.edu/index.php/Main_Page
Online historical documents for multiple European countries.
Stefan's Florilegium
http://www.florilegium.org/
Notes on a little bit of everything.
Cariadoc's Miscellany
http://www.pbm.com/~lindahl/cariadoc/miscellany.html
This and that from Cariadoc of the Bow
British Library
http://www.bl.uk/treasures/treasuresinfull.html
http://www.bl.uk/onlinegallery/ttp/ttpbooks.html
Treasures of the library scanned and available online, including several period sources.