VEGETIUS (FLAvjUS VEGETIUS RENATUS)  , a celebrated military writer of the 4th century . Nothing is known of his life, station and military experience, save that in MSS. he is called vir illustris and also comes . His treatise, Epitoma rei militeris, sive institutorum :rei militaris libri quinque, was dedicated to the reigning emperor ( ? Theodosius the Great) . His sources, according to his own statement, were Cato, Cornelius Celsus, Frontinus, Paternus and the imperial constitutions of Augustus, Trajan and Hadrian . The book, which is a con-fused and unscientific compilation, has to be used with great caution, but is none the less invaluable to the student of the ancient art of war . The first book is a plea for army reform, and vividly portrays the military decadence of the empire . The third contains a series of military maxims which were (rightly enough, considering the similarity in the military conditions of the two ages) the foundation of military learning• for every European commander, from William the Silent to Frederick the Great . When the French Revolution and the " nation in arms" came into history, we hear little more of Vegetius . Some of the maxims may be mentioned here as illustrating the principles of a war for limited political objects (see Aiusy) with which he deals . All that is advantageous to the enemy is disadvantageous; to you, and all that is useful to you, damages the enemy "; " No man is to be employed in the field who is not trained and tested in discipline "; It is better to beat the enemy through want, surprises and care for difficult places (i.e. through manoeuvre) than by a battle in the open field "--maxims that have guided the leaders of professional armies in all countries and at all times, as witness the Chinese generals Sun and Wu (see E . F .

Calthrop, The Book of War,

London, 1908) . His " seven normal dispositions for battle," once in honour amongst European students of the art of war, are equally ludicrous if applied to present-day conditions . His book on siegecraft is important as containing the best description of late. empire and medieval siege matters, &c., and from it amongst other things we learn details of the siege engine called onager, which afterwards played a great part in sieges . • The fifth book is an account of the material and personnel, of the Roman navy . In manuscript, Vegetius's work had a great vogue from the first, and its rules of siegecraft were much studied in the middle ages . It was translated into English, French and even Bulgarian before the invention of printing . The first printed editions are assigned to Utrecht (1473), Cologne (1476), Paris (1478), Rome (in Ve4eres dere mil. scriptures, 1487), and Pisa (1488) . A German translation by Ludwig Hohenwang appeared at Ulm in 1475 . Vegetius's position as the premier military critic was thenceforward assured . As late. as the 18th century we find so eminent a soldier as Marshal Puysegur basing his own works on this acknowledged. model, and the famous Prince de Ligne wrote " C'est un livre:d'or." The fullest and most important modern edition is that of Karl Lang (Leipzig, 1869) . An English version through the French was published by Caxton in 1489 . For a detailed critical estimate of Vegetius's works and influence see Max Jahns, Gesch. der Kriegswissenschaften, i .

109-125 .