The Fall of the Byzantine Empire, A Chronicle by George Sphrantzes (1401-1477)

A remarkable eye-witness account of the fall of the Eastern Roman Empire. Today it is generally called the Byzantine Empire, a term coined in the seventeenth century. In Sphrantzes's day it was simply called the Roman Empire. It had been established by Constantine the Great on a site that had been occupied since the seventh century BC by the ancient Greek colony of Megara, Byzantium. The Byzantine Empire had existed for over 1000 years, until it's capital Constantinople finally succumbed to the Ottoman Turks in 1453.
Sphrantzes lived through the reign of the last two emperors, John VIII Palaeologus, 1425-1448, and Constantine XI Dragases, 1448-1453, and was present at the siege of Constantinople, and the onslaught of the Ottomans. He survived and lived on for another thirty years or so.