 Complete the following phrase:  Constanss son Constantine IV 668685 had been made co-emperor in 654, and ruled in the east while his father campaigned in the west 662668, succeeding him on the latters death. Almost immediately he had to deal with Arab attacks on Amorium in Phrygia in 646 and Chalcedon in Bithynia. This was followed by the capture of Cyzicus in Mysia 670, as well as Smyrna and other coastal cities, finally 