Roman Emperor Of The West Flavius Popilius Magnentius, died in August, 353. He is said to have been of a German family of Gaul, and taken captive by Constantius Chlorus or Con-stantine. Under the latter he rose to the rank of count. Having been intrusted by Constans with the command of the Jovian and Herculean legions, which had been substituted for the ancient praetorian guards at the remodelling of the empire by Diocletian, he availed himself of his office to plot the emperor's overthrow. On Jan. 18, 350, presenting himself in imperial robes at a great banquet given by one of the conspirators at Autun, he was immediately saluted with the title of Augustus; and assassins sent for the purpose having despatched Constans, Magnentius was acknowledged as emperor by all the western provinces except Illyria. Constantius, on hearing of his brother's murder, hastened from the confines of Persia and defeated Magnentius in a most sanguinary battle at Mursa (Eszek) on the Drave in 351, and in the passes of the Cottian Alps in 353. These disasters led to the defection of all the countries that had recognized the usurper, who thereupon committed suicide.