It was under Alp Arslān that the Turks first invaded the Roman Empire.[286] Having temporarily satisfied his ambition in the West,[287] he returned to his capital, and formed the project of crossing the Oxus and invading the countries whence his ancestors had come. His career was, however, cut short in A.H. 465 (1063) by a mortal wound received at the hands of a man whom he had condemned to death.[288] He was succeeded by his son Melik Shāh, whose claims were disputed by several rivals,[289] but these were disposed of with little difficulty. In A.H. 446 (1073) he engaged in warfare with Altagin, the Turkish Khān of Samarkand, who, on hearing of the death of Alptagin, had presumed to lay siege to Tirmiz, a town included in the Seljūks’ realms, though it lay on the right bank of the Oxus.[290] He soon drove the Khān back, and forced him to sue for peace. Melik Shāh apparently remained on peaceful terms with the Turks until A.H. 482 (1089), when, in response to a call from the oppressed inhabitants of Transoxiana, he crossed the great river and made himself master of Bokhārā and Samarkand. Pushing beyond the last-named city, he threatened to invade the territory of the Khān of Kāshghar,[291] who, overcome by fear, consented to recognise the suzerainty of the Seljūks,[292] both in his coins and in the public prayers. At the zenith of his fortunes the great Sultan held sway from the frontiers of China up to the gates of Constantinople. August Müller[293] aptly compares Alp Arslān and Melik Shāh with Trajan and Hadrian. Brilliant as were the military successes of Melik Shāh, they are cast into the shade by his cultivation of the peaceful arts and his sedulous care for the development of his territories. Though five years passed by ere he was firmly established on his throne, the remaining fifteen years of his reign were attended by a degree of internal prosperity, an advance in literature and learning, which will ever associate his name with one of the most brilliant epochs in the history of Islām. There is, however, one great blot on his escutcheon: his treatment of his able and faithful minister, Nizām ul-Mulk. Influenced by lying reports brought to his ears by the enemies of the vezīr, he degraded his devoted servant and indirectly brought about his death. For, shortly after Nizām ul-Mulk’s removal from office, he was murdered by an assassin,[294] employed perhaps by his successor in office, who feared a change in the Sultan’s sentiments, A.H. 485 (1092). Melik Shāh did not long survive the fallen minister. Within a month he was seized with a violent illness, which terminated his life in the thirty-eighth year of his age.