Led by Leo's brother Nikephoros Phokas, the Byzantines now launched a sustained offensive that by 969 had conquered Cilicia and northern Syria around Antioch, and resulted in the vassalization of Aleppo itself.

In the middle of the 10th century, after a period of expansion on its eastern frontier, led by John Kourkouas, at the expense of the Muslim border emirates,[1] the Byzantine Empire was confronted by the Hamdanid prince Sayf al-Dawla.

In 945, Sayf al-Dawla made Aleppo his capital and soon established his authority across northern Syria, much of the Jazira (Upper Mesopotamia), and what remained of the Abbasid Caliphate's frontier districts (thughūr) with Byzantium.

[9] In November 950, Leo scored a significant success against Sayf al-Dawla, who had previously advanced deep into Byzantine Asia Minor from Cilicia and defeated Bardas in battle.

[6][13][14] In the early summer of 960, Sayf al-Dawla saw an opportunity to reverse his recent setbacks and re-establish his position: the best troops of the Byzantine army, and Nikephoros Phokas himself, departed the eastern front for an expedition against the Emirate of Crete.

[17][18][19] The 11th-century Christian Arab chronicler Yahya of Antioch, however, reports that Leo had been appointed Domestic of the East and that he had remained on the eastern front throughout 959–960, leading raids into the Hamdanid domains up until the invasion of Sayf al-Dawla.

[16] At the head of a strong cavalry force—the numbers reported in the sources vary from 3,000 to as many as 30,000[20][21]—Sayf al-Dawla invaded Byzantine territory, and advanced unopposed as far as the fortress of Charsianon, capital of the theme of the same name.

According to the historian William Garrood, this fact, along with the great depth of penetration, and the long duration of the raid, points to it being "a grand campaign of destabilisation of the border" rather than an expedition with specific targets in mind.

The contemporary Byzantine historian Leo the Deacon gives a vivid portrait of the Hamdanid prince, who, elated at the success of his raid and full of self-confidence, sped back and forth alongside his troops on his horse, a mare "of extraordinary size and speed", throwing his spear in the air and catching it again with remarkable dexterity.

[36] On 8 November 960, the Hamdanid army entered the pass, where, according to Leo the Deacon, they "had to crowd together in the very narrow and rough places, breaking their formations, and had to cross the steep section each one as best he could".

Once the entire Arab force, including their train and their captives, was in the pass, with the vanguard already nearing the southern exit, Leo Phokas gave the signal for the attack.

B. Bikhazi, have commonly considered the defeat at Andrassos as a decisive engagement that destroyed Hamdanid offensive abilities for good and opened the path for Nikephoros Phokas' subsequent exploits.

[49][50][51] Garrood, on the other hand, argues that the Hamdanid ruler had been able to recover from similar failures on previous occasions and that the forces of Naja and his Tarsiot allies remained intact; furthermore, unlike the disasters that followed, his authority does not appear to have been challenged in the aftermath of the battle.

[52] Nevertheless, Sayf al-Dawla's 960 raid was the last of this scale and ambition,[52] and the Byzantines did not allow him to recover his strength: as soon as Nikephoros Phokas returned victorious from Crete in mid-961, he resumed the offensive in the east.

Sayf al-Dawla's attempts to halt the Byzantine advance in Cilicia failed, and Nikephoros Phokas, with an army reportedly 70,000 strong, took Marash, Sisium, Duluk, and Manbij, securing the western passes over the Anti-Taurus Mountains.

The disease limited Sayf al-Dawla's ability to intervene personally in the affairs of his state; he soon abandoned Aleppo to the charge of his chamberlain, Qarquya, and spent most of his final years in Mayyafariqin, leaving his senior lieutenants to carry the burden of warfare against the Byzantines and the various rebellions that increasingly occurred in his domains.

[65][66] The fall of the great metropolis of northern Syria was soon followed by a treaty between the Byzantines and Qarquya, the ruler of Aleppo, which made the city a tributary vassal.

Byzantine rule was extended over the entirety of the former thughūr, as well as the coastal strip of Syria between the Mediterranean Sea and the Orontes River until the environs of Tripoli, Arqa, and Shayzar.