The Historians' History of the World, subtitled A Comprehensive Narrative of the Rise and Development of Nations as Recorded by over two thousand of the Great Writers of all Ages, is a 25-volume encyclopedia of world history originally published in English near the beginning of the 20th century. It was compiled by Henry Smith Williams, a medical doctor and author of many books on medicine, science, and history, as well as other authorities on history, and published in New York in 1902 by Encyclopædia Britannica and the Outlook Company. It was also published in London printed by Morrison & Gibb Limited, of Edinburgh. A second edition was published in 1907 in London by The Times. Two further volumes were subsequently released in the 5th edition of 1926, titled "These eventful years" and dealing with the First World War, published by Encyclopaedia Britannica.

Volume VII: The later Roman Empire

Part XI: The History of the Later Roman Empire states that, along with over 75 additional authors, the work is based chiefly upon the following authorities: Agathias, Appian, Augustan History, J. B. Bury, Henry Fynes Clinton, George Kedrenos, Anna Komnene, Cassius Dio, Doukas (historian), Einhard, Eutropius (historian), George Finlay, Heinrich Gelzer, Edward Gibbon, Wilhelm von Giesebrecht, Ferdinand Gregorovius, Gustav Hertzberg, Thomas Hodgkin (historian), Jordanes, John Malalas, Procopius, Leopold von Ranke, Strabo, Tacitus, Marcus Velleius Paterculus, Georg Weber, Joannes Zonaras, and Zosimus.

Beginning with the reign of Arcadius in 395, Book I: The Later Roman Empire in the East deals with the Eastern Roman Empire through to the Fall of Constantinople in 1453, detailing as well the Siege of Constantinople (1204) by the members of the Fourth Crusade which led to the short-lived Latin Empire along with the various incidents in the history of Constantinople with several chapters dedicated to Justinian I; Book II The Later Roman Empire in the West begins with Odoacer and the Visigoth invasion of Italy followed by the Lombard invasion of Italy, the Carolingian dynasty and Charlemagne and the birth of the Holy Roman Empire up to the Investiture controversy and Henry V, Holy Roman Emperor.