The thematic capital, Amorium, was also a frequent target of the Arabs. It was attacked already in 644, captured in 646, and briefly occupied in 669. The Arabs reached it again in 708 and besieged it without success in 716, during their march on Constantinople. The tide of the Arab attacks ebbed in the 740s, after the Byzantine victory at the Battle of Akroinon and the turmoil of the Third Fitna and the Abbasid Revolution, and under Emperor Constantine V (r. 741–775), the Anatolics spearheaded the Byzantine campaigns into Arab-held territory. This in turn provoked the reaction of the Abbasid Caliphate, which in the quarter-century after 780 launched repeated invasions of Byzantine Asia Minor. Thus the Anatolics suffered a heavy defeat at Kopidnadon in 788, and Amorium was threatened again in 797. In the early years of the 9th century, Cappadocia was the focus of Arab attacks, which culminated in the great invasion of 806 led by Caliph Harun al-Rashid (r. 786–809) himself, which took Heraclea Cybistra and several other forts.