Conflict has raged for years between Romans…

Conflict has raged for years between Romans and Persians in northern Mesopotamia, with neither side a clear-cut victor.

Nearly every year the Persians have attacked and pillaged Roman territory; the Mesopotamian towns are besieged, and the great fortress cities of Nisibis, which Shapur has besieged three times without success, and Amida, continue to resist.

Constantius has fought Shapur conscientiously, but his generals have been mediocre, except for Urisicinus, and he himself is clumsy.

However, Shapur is in 350 distracted by the appearance on his eastern frontier of a new enemy, the nomadic Chionites or Xionites, sometimes identified with a tribe known as Red Huns but whose origins remain controversial.