Crowd-Sourcing Research: Name Your Favorite Source(s)!

I write medieval romance. That means doing research–and lots of it. I can’t make any assumptions about the places where my books are set. I’ve been to England–the setting for my current manuscript–several times, but tracts of English countryside that may have been forested for the past 500 years may have been pastureland in the 12th century, the time period of my current manuscript. And if my characters in 12th century Norfolk pick up a fork to eat, readers in the know will question every oth...