What was a RESULT of Justinian's attempt to reunite the eastern and western halves of the old Roman Empire? The effort was a complete failure. All of the western lands of the old empire became part of the Byzantine Empire. The attempt led to a return of prosperity to Rome and Italy. Italy and North Africa were conquered, but then lost to new invaders.
"Italy and North Africa were conquered but then lost to new invaders" The short victory was a bit of an illusion, however, because Justinian's efforts brough about endless conflict and terrible war.