The barbarian invasions of the Balkans in the 3rd century had devastated the region, helping persuade Aurelian to strategically abandon the province of Dacia – probably in the late summer of 271, when the Dacian legions were needed for his campaign against Palmyra. The province’s troops were relocated south of the Danube, along with those civilians who chose to move. Many people remained behind and continued to trade with Rome; these Daco-Romans may have been the ancestors of today’s Romanians, although this is still debated.in wikipedia
By January 272 Aurelian’s march to the east had reached Byzantium, where he began preparations for the invasion of Zenobia’s holdings in Asia Minor. In response, Zenobia and her son Vaballathus proclaimed themselves Augusta and Augustus (empress and emperor) in March or April 272, finally assuming a stance of open rebellion against Aurelian.in wikipedia
In spring 272 Aurelian and his army crossed the Bosporus into Asia Minor, where Ancyra (Ankara) in Galatia submitted without a struggle. The first resistance was in Tyana in Cappadocia, which enraged Aurelian when it refused to open its gates to him. However, when the city was betrayed to him, Aurelian was merciful, although he had all the dogs killed to fulfil a vow he had made that he “would not leave even a dog alive” in the town.in wikipedia
In spring 272 Aurelian sent a naval expedition under the command of M. Aurelius Probus—the future emperor Probus—from Byzantium to retake Egypt from Zenobia. Probus landed near Alexandria in early May and, despite some close fighting, captured that city by the end of the month with the aid of reinforcements. The rest of the province soon fell to his forces, once again securing the province’s vital grain supply for Rome.in wikipedia
Marching south from Tyana, Aurelian neared Antioch in late spring 272. East of this important city, the empress Zenobia and her general Zabdas assembled a force of archers and heavily armored cavalry to meet the Romans in battle. Although inferior in heavy cavalry, Aurelian harassed the Palmyrenes with light cavalry until they were exhausted and then crushed them. Defeated, Zenobia fled to Emesa.in wikipedia