Constans in Harpers Dictionary of Classical Antiquities

The youngest of the three sons of Constantine the Great and Fausta. After his father's death he received (A.D. 337) as his share of the Empire, Illyricum, Italy, and Africa. His territory was invaded by his brother Constantine, who was defeated and slain in the invasion (340 A.D.). Constans became supreme over the whole Western Empire, but the weakness and profligacy of his character made him despised and disliked so that in 350 he was slain by the troops of the usurper Magnentius (q.v.).