 Complete the following phrase:  The Bulgars of Asparuh moved westwards to what is now Bessarabia, subdued the territories to the north of the Danube in modern Wallachia, and established themselves in the Danube Delta. In the 670s they crossed the Danube into Scythia Minor, nominally a Byzantine province, whose steppe grasslands and pastures were important for the large herd stocks of the Bulgars in addition to the grazing grounds to the west of the Dniester River already under their control. In 680 the Byzantine Emperor Constantine IV r.668685, having recently defeated the Arabs, led an expedition at the head of a huge army and fleet to drive off the Bulgars but suffered a disastrous defeat at the hands of Asparuh 