 The ground work for his successes had certainly been laid by others : Michael III , who broke the power of Melitene at Lalakaon ; Basil I , who destroyed the Paulicians ; Leo VI the Wise , who founded the vital theme of Mesopotamia ; and Empress Zoe , who extended Byzantine influence again into Armenia and founded the theme of Lykandos . It was Kourkouas and his campaigns , however , that incontrovertibly changed the balance of power in the northern Middle East , securing the frontier provinces against Arab raids and turning Byzantium into an expansionist power . In the words of historian Steven Runciman , " a lesser general might [ ... ] have cleared the Empire of the Saracens and successfully defended its borders ; but [ Kourkouas ] did more . He infused a new spirit into the imperial armies , and led them victoriously deep into the country of the infidels . The actual area of his conquests was not so very large ; but they sufficed to reverse the age @-@ old roles of Byzantium and the Arabs . Byzantium now was the aggressor ... [ John Kourkouas ] was the first of a line of great conquerors and as the first is worthy of high praise . " 
