The LCSH helps you find related information on your topic. If you locate relevant books in a keyword search, try clicking on the subject links to find more resources on this subject. Here are some examples of general subject headings related to the Middle Ages (you'll be focusing on the period of the 11th-12th centuries):
You can also locate materials by LC call number ranges. For example, general Medieval history is under D111-D203, and Great Britain Medieval History is under DA129-DA260 (there are other regions under the D call #s). This is good to know if you are just looking in the library stacks (these resources are on the 7th floor of the Blue wing).
As a digital repository for the nation's great research libraries, HathiTrust brings together the immense collections of partner institutions. It was initially conceived as a collaboration of the thirteen universities of the Committee on Institutional Cooperation, the University of California system, and the University of Virginia to establish a repository for those universities to archive and share their digitized collections, and quickly expanded to include additional partners with fast growing treasure of digitized collections.
Covers literature and criticism, history, the visual and performing arts, cultural studies, education, political science, gender studies, etc. Contains current full text scholarly journals which cover these fields and a significant collection of recent scholarly books.
Naxos Music Library [NML] is the world´s largest online classical music library. Currently, it offers streaming access to more than 107,410 CDs with more than 1,565,400 tracks of both standard and rare repertoire. Over 800 new CDs are added to the library every month.