Here are some resources I thought I’d throw out there:
Guibert De Nogent’s Monodies and On the Relics of Saints
An excellent firsthand source written by a monk in the late 11th and early 12th centuries. This was a major source for my upcoming novel “The Vimana Incident.”
Roger of Wendover’s Flores Historiarum
An early historian recounts English history up to the year 1235 in a slightly embellished version. There is also a continuation by another historian, Matthew Paris. This was a major source used in my upcoming novel “The Linen Buttefly” and my short story “The Last Days of Guillaume de Longespee.” Sadly the second volume, which the PSU library has, is next to impossible to find online and is very difficult to find in print anywhere but the first volume is here:
https://archive.org/details/rogerofwendovers01rogemiss
The Internet Medieval Sourcebook
A free and extremely useful online resource for firsthand sources. This was a source nearly all of my history professors at PSU have recommended:
http://www.fordham.edu/halsall/sbook.asp
Terry Jones’ Medieval Lives
You have to take his cynical and contrarian tone with a grain of salt, but the series is full of useful information nonetheless. This was a major source for my novels “The Goldenlea” and “The Linen Buttefly.”
https://www.youtube.com/channel/SWs-Gqsjg9y-8
The Medieval Machine: The Industrial Revolution of the Middle Ages by Jean Gimpel
This hasn’t been used consciously as a source but it is nonetheless a fascinating (if a bit dry and technical) read that will blow away your conceptions about the mechanical advancement of the Middle Ages.