by a war among his sons, which gave Mohammad an opportunity. The capture of Konia (Iconium) and Caraman (Laranda) secured him the rule of the whole land except Seleucia on the south-eastern coast, and he assigned this important province, which he systematically dispeopled, to his youngest son Mustafa. This conquest, following upon that of Trebizond, brought on the inevitable struggle with the rival oriental monarch, Uzun Hasan the Turcoman. He had extended his sovereignty from the Oxus to the limits of Caramania, and a large part of Persia was under his dominion. Caramania was a useful "buffer-State." Uzun Hasan wrote to Mohammad demanding the cession of Trebizond and Cappadocia, and complaining of the execution of King David Comnenus. Mohammad promised to meet him at the head of an army. The Turcoman invaded Caramania to restore the dethroned princes and took Tokat (1471); but in the next year Mustafa defeated him in a hard-fought battle by the shores of Lake Caralis. The decisive battle was fought in 1473 (July 26) on the banks of the Euphrates near Terdshan. Mustafa and his brother Bayazid led each a wing of their father's army, and were opposed respectively to the two sons of Uzun Hasan. The strife swayed long, before it was decided by the Ottoman artillery. Mohammad wrote himself: "the fight was bloody, costing me the bravest of my pashas and many soldiers; without my artillery, which terrified the Persian horses, the issue would have been longer doubtful." The significance of this victory, of which Mohammad probably thought more than of all his achievements except the capture of Constantinople, lay in its securing Caramania and Asia Minor. He was now free to follow out his schemes of conquest in Europe.
The Roumanians north of the Danube had long ago been entangled in the ecumenical struggle. Mirtschea the Great, prince of Wallachia, who by astute diplomacy steered his way between Hungary and Poland, had fought for Christendom in the disastrous battles of Kosovo (1389) and Nicopolis (1396), but was obliged to submit to the suzerainty of Mohammad I (1412). After his death civil wars between pretenders desolated and demoralised the principality for forty years, until (1456) a strong man came to the helm in the person of Vlad IV. The princes of Wallachia and of Moldavia were elected by the people out of the princely families; but they had unlimited power, being the supreme judges, with control over the life and death of their subjects, and the complete disposal of the public revenue. Thus only a steely-hearted, resolute man was wanted to restore order; and Vlad accomplished this by a policy of relentless severity which has handed him down to history under the name of the Devil or the Impaler. Having assured his throne and established friendly relations with his neighbours Moldavia and Hungary, he defied the Turk by refusing the tribute of children which Wallachia paid like other subject-lands. Mohammad sent an envoy, Hamza Pasha, accompanied by 2000 men, with secret instructions to seize Vlad's person.