• NetSERF
      Gateway to Medieval resources. - see especially Architecture: Churches and Cathedrals
  
• Online Medieval Sources Bibliography
  A searchable bibliography of medieval texts.
• The Labyrinth
      A web server for Medieval Studies, sponsored by Georgetown Univ.

• WESS Medieval and Renaissance Web
      Designed to provide access to scholarly resources in all aspects of the Western Middle Ages and the Renaissance.
• British History Online
  Full text of documents on medieval and early modern British history.
• Fine Rolls of Henry III
• Bodleian Library Manuscript Images
• Illuminated manuscripts in France
  

Villard, de Honnecourt. Facsimile of the sketch-book of Wilars de Honecort, an architect of the thirteenth century; with commentaries and descriptions by M. J. B. A. Lassus and by M. J. Quicherat, trans. and ed. with many additional articles and notes, by the Rev. Robert Willis.   London, J. H. and J. Parker, 1859.  Lilly Locked Stacks NA1053.V6 A3 1859  

Duke The RubensteinLibrary (Rare Book, Manuscript, and Special Collections Library) has a vast array of  rare books and manuscripts from the Renaissance era.  Since many titles are not extensively cataloged, it's best to consult RBMSCL reference librarians directly on what might be there in a certain area.

EXAMPLE:

Medieval trade in the Mediterranean world; illustrative documents translated with introduction and notes