 Theoktistos continued the persecution of the Paulicians , which had been initiated by Theodora in 843 . Many fled to Arab territory , where with Umar al @-@ Aqta 's aid they established a state of their own at Tephrike under their leader Karbeas . Theoktistos concluded a truce with the Abbasid Caliphate and arranged an exchange of prisoners that took place on 16 September 845 . Nevertheless , in the same year , the execution of the surviving Byzantine prisoners from the Arab Sack of Amorium in 842 took place in the Abbasid capital , Samarra . After 845 , the Arab raids in the east died down for a few years after a winter raid launched by Ahmad al @-@ Bahili , the Abbasid emir of Tarsus , was defeated by the strategos of Cappadocia . They did not recommence until 851 , when the new emir of Tarsus , Ali al @-@ Armani , launched summer raids for three successive years , albeit with little apparent impact . The Byzantines responded with a naval expedition in 853 that sacked the port of Damietta in Egypt , while in the next year a Byzantine army invaded Arab lands in Cilicia and sacked Anazarbus . Around 20 @,@ 000 prisoners were taken , some of whom were executed on Theoktistos ' orders after they refused to convert to Christianity , probably as a gesture of retaliation for the Caliphate 's execution of the prisoners of Amorium in 845 . 
