Towards the end of 7th century, the Byzantine hegemony in Anatolia came to an end. First, the Umayyeds gained sovereignty and then the Abbasides came into power, ruled until the end of the 9th century. At the end of 10th century, the Byzantine Empire restored its hegemony in entire Anatolia.
Byzantine Emperor Vasil II spent the last years of his life leading some activities in the Caucuses. After the death of Gagik I (990-1020) of the Armenian Bagratuni dynasty, chaos started in this region, which gave the Byzantine Emperor a chance to interfere with the Caucuses successfully. Thus, a part of Georgia and Van region were annexed to the Byzantine Empire and the Armenian Ani dynasty was succeeded by Ionnas Smbat, the son and life-long heir apparent of Gagik. After Ionnas Smbat died Byzantine Empire had annexed the dynasty.
The Byzantine Empire not only annexed the territories in this land, where Armenians lived but also "removed the commanders of Armenian nation from their own houses and states and exiled these commanders with them" as Mateos of Urfa stated. The situation was really suitable for Seljuks to enter Anatolia. Christian defenses in the region had weakened and Byzantine army also lost power due to domestic political disputes and military rebellions.
The Seljukian Crown Prince Hasan commenced raids to Van Lake region in 1047-1048. Ibrahim Yinal who was appointed as Azerbaijan Governor General, in collaboration with Kutalmish defeated the Byzantine Army, which was under the command of Liparit, Aaron and Katalon, in Pasin Plains in September 1048, upon the order he took from Tugrul Beg.
Romanos VI. Diogenes, who obtained power by marrying Byzantine Emperor Konstantin Dukas's (May 1067) wife after the emperor's death, promptly took the control of the war against the Seljuks. However, due to the weakening of his army, he gathered an army mostly consisting of foreign soldiers (Pecheneg, Oghuz, Norman, Frank, Armenian, Slav, Bulgarian, German, Caspian, Georgian) with great difficulties.
According to Islamic and Christian resources, this army mobilized by the Byzantine Emperor, added up to a total between 200.000 and 600.000 soldiers. The Byzantine Emperor, before moving towards Malazgirt, heard the news that Armenians acted more brutally than the Turks did and he swore to destroy Armenian community after the war.
On 26th August 1071, the Byzantine Emperor attacked onto Sultan Alparslan's army at a location around Van Lake near Malazgirt with his paid army, which was superior in number but undisciplined and consisting of foreign soldiers. However, his army was routed and almost destroyed by Alparslan's army, and even the Emperor himself was captured. Alparslan made peace with Emperor Diogenes and sent him to Istanbul back to his throne with a great ceremony.
Mateos of Urfa, after listening to people who had experienced these events personally wrote about it and expressed Byzantine behavior towards Armenians who lived for so long under the sovereignty of Byzantium:
"... They (Romans) caused Catholicos (Haçik) to suffer from various types of torture because of his sect. As we heard, they tortured him with fire, but he came out of fire safe and sound."
"Two years later (993-994) the Great Roman Duke attacked the Armenians with a powerful army, dashing at Christians, he killed them and captured them. He, like a poisonous snake, brought death everywhere, and thus took the place of godless nations."
How did Turks behave the Armenians who fought together with Byzantium against Turks? Did Turks despise and oppress them or burn their churches and monasteries as the Byzantine rulers did? Mateos of Urfa recorded the tolerance shown to all non-Moslem minorities living under Seljukian rule, especially the Armenians:
"In 539 (27th February 1090-26th February 1091) the Armenian Catholicos Barseg went to Conqueror Sultan Melikshah. Seeing that Christians are oppressed at some places, taxes are demanded from churches of God and clergy, and bishops are oppressed in monasteries for taxes, Catolicosis decided to enter the presence of Iran's and all Christians' magnanimous and pleasant Sultan and tell him all problems. The Sultan admitted signor Barseg to his presence paid him a great compliment and fulfilled his wishes. The Sultan exempted all churches and monasteries and the clergy from taxes and gave Armenian Catolicosis, firmans and saw him off with compliments."
As it can be understood from the statements above, Seljukian Turks showed Armenians as well as the other non-Muslim subjects, the tolerance, which had not been shown by the Byzantine Empire and ensured them that he will protect their religion and social lives. This tolerance continued in the period of Anatolian Seljuk Empire as well. In spite of all the tolerance shown to them, it is also known that Armenians sometimes supported to the Byzantine Empire and also, at the time of the Crusades, they reinforced the Crusade Armies.
REFERENCE: Yildirim, Dr.Hüsamettin, Ermeni Iddialari ve Gerçekler, Ankara, 2000.