source: His first action was to move against the barbarian tribes that had been gathered by Aurelian for his Eastern campaign, and which had plundered the Eastern Roman provinces after Aurelian had been murdered and the campaign cancelled.
target: His first action was to move against the barbarian tribes. The tribes had been gathered by Aurelian for his Eastern campaign. The barbarians plundered the Eastern Roman provinces. They did so after the murder of Aurelian. The campaign was cancelled after the murder.
references: His first action was to move against the barbarian tribes. The tribes had been gathered by Aurelian for his Eastern campaign. The barbarians plundered the Eastern Roman provinces. They did so after the murder of Aurelian. The campaign was cancelled after the murder.