Marcus Sedatius Severianus (105–161 or 162)[1][2] was a Roman senator, suffect consul, and general during the 2nd century AD, originally from Gaul.

[4] Another inscription[I 2] mentions that Severianus is from the tribe Quirina, which indicates that his ancestors had become Roman under either Claudius or the Flavians, like nearly all of the inhabitants of Gaul who had become Quirites during the 1st century.

[6] Severinus' full pedigree was: Marcus Sedatius C. f. [i.e. Gaii filius] Severianus Iulius Acer Metillius Nepos Rufinus Ti.

[I 2] The transliteration of his name into Ancient Greek was: Μ. Σηδάτιος Σεουηριανὸς;[I 3] The power of Severianus' wealthy family, the Sedatii, came from trade and commerce.

The possible marriage of Severianus' father to Julia Rufina may have been a way of confirming the association between winemakers and land owners in Gaul.

[9] The first magisterial position which we know Severianus held was that of quaestor of Sicily; he would have supervised the provincial treasury and audited its accounts.

[I 4] The traditional Republican magistracy of tribune of the plebs followed, another prestigious position which had lost its independence and most of its practical functions.

Next he served as a praetor, afterwards commanding the Legio V Macedonica which was stationed in Troesmis in Moesia Inferior on the lower Danube.

Historian Marcel Le Glay suggests that his promotion was due to the support of Publius Mummius Sisenna Rutilianus,[16] the governor of Asia who is famous as a follower of the self-described prophet Alexander of Abonoteichus thanks to the works of Lucian.

In the summer of 161, the Parthian Vologases IV invaded Armenia, expelled the ruler Sohaemus placed there by the Romans, and installed his own relative Pacoras as king.

[22][23] Severianus led a legion (perhaps the IX Hispana[24]) into Armenia, but was trapped by the Parthian general Chosrhoes at Elegeia, a town just beyond the Cappadocian frontiers, near the headwaters of the Euphrates.

[5] Co-Emperor Lucius Verus (he ruled with his adoptive brother Marcus Aurelius) took command against the Parthians and brought in reinforcements on a large scale.