Many of the sites listed here deal with different periods of European and Russian history.
EuroDocs
http://eudocs.lib.byu.edu/index.php/Main_Page
Historical Research in Europe (U.Wisc. guide)
http://digicoll.library.wisc.edu/HistResEur/
Perseus Project (ancient Greece & Rome)
http://www.perseus.tufts.edu/hopper
Labyrinth: Medieval Resources
http://labyrinth.georgetown.edu/
Center for Reformation & Renaissance Studies
http://www.crrs.ca/
Early Modern Resources
http://www.earlymodernweb.org.uk/emr/
British Museum
http://britishmuseum.org/research/libraries_and_archives.aspx
Russian & Soviet History Resources
http://facstaff.bloomu.edu/hickey/Russian%20and%20Soviet%20History%20Resource%20Page.htm
These sites have all been visited and the addresses proofread. Should you experience any problems or notice any errors, however, please contact cmartin@suffolk.edu.