Other Muslim military ventures were met with outright failure. Despite a naval victory over the Byzantines in 654 at the Battle of the Masts, the subsequent attempt to besiege Constantinople was frustrated by a storm which damaged the Arab fleet. Later sieges of Constantinople in 668–669 (674–78 according to other estimates) and 717–718 were thwarted with the help of the recently invented Greek fire. In the east, although Arabs were able to establish control over most Sasanian-controlled areas of modern Afghanistan after the fall of Persia, the Kabul region resisted repeated attempts at invasion and would continue to do so until it was conquered by the Saffarids three centuries later.