Latin Language

For the study of Latin and Latin early Christian authors, Latinitium is a useful repository with links to resources for learning Latin.  Latinitium includes links to PDFs of books and grammars as well as links to online libraries of Latin texts, including the Bibliotheca Augustana.  

Catalogue of Digital Editions

The Catalogue of Digital Editions keeps track of primary sources without respect to chronology or geography, and early Christian sources strongly feature in a search on antique sources. Navigation and display are very accommodating, and underlying data is RDF-compliant. Other filtered results: Greek Latin Armenian Syriac

Christian History Institute

Christian History Institute Non-profit organization promoting the study of church history, including many primary sources from the early church and the medieval period.