This book covers a vast period in the history of the Byzantine Empire from the accession of the Comneni dynasty to the fall of Constantinople in 1204. At the center of the story is the figure of Emperor Alexios I, whom contemporaries called the “13th Apostle,” as well as his activities to restore the integrity of Byzantium and eliminating the mortal threat from the Turks and Pechenegs at the end of the 11th century. In addition, the book reveals the circumstances and course of the first Crusades.