History
Ancient and Medieval History 

• ABZU: Guide to the Ancient Near East--this guide from the University of Chicago's Oriental Institute is a prime resource for history, religion, art and archaeology.
• Ancient African History Sources
• Ancient Mesoamerican Civilizations
• Byzantine and Medieval Studies Sites 
• China: Ancient World Cultures -- a summary, timeline and texts, plus essays.
• Egyptology Resources
• Medieval India
• Internet Medieval Source Book-- Links to full texts of church documents, works of church fathers, literary and political texts
• Medieval Studies
• Medieval Technology Pages -- provides referenced information on technological innovation and related subjects in western Europe during the Middle Ages.  Also includes a timeline of innovations from 500 to 1600 A.D.
• Online Transcriptions and Translations in Medieval Studies
• Perseus Project--a massive project documenting the classical world, with a concentration on Greece