The records of the reign of Alexander Severus contained in the extant works of ancient historians are essentially insufficient, and information on many of the questions of his history has to be sought from other sources. Circumstances have conspired in several ways to obscure the Emperors history. With one exception contemporary writers possessed little insight or ability, and Dio, - the exception, - practically closed his narrative with the death of Elagabalus. Later writers, also With one exception, were mere compilers, and though Ammianus Marcellinus, - the exception, - began his history of Rome with Nerva, the early books epitomising the history of the first two hundred and fifty seven years are lost.