Renaissance/Crusades/Black Death
The Renaissance
Encyclopedia Britannica - European Renaissance
Live Science: The Renaissance: The 'Rebirth' of Science & Culture
The Myth of the Renaissance in Europe
The Crusades
The Crusades - History.com
The Crusades: A Complete History
Apocalypticism Explained: The Crusades
How the Crusades Worked - HowStuffWorks.com
The Crusades (Google Doc)
The Black Death
The Black Death: The Greatest Catastrophe Ever
The Black Death, 1348
Plague - National Geographic
Black Death - BBC History
The Fall of Rome (Western Europe)
Feudalism
The absence of the Roman Empire fueled Western civilization
History of the Fall of Rome
The Fall of Rome (Eastern Europe)
History of Istanbul
Constantinople / Istanbul
Ancient History Encyclopedia - Constantinople