The frontier country of the Amu Darya, the river classical writers called the Oxus — the boundary between the Iranian world and the steppe, where Alp Arslan was fatally stabbed in 1072.
The Oxus region is not a place with a boundary but a frontier along a river. The Amu Darya runs some 2,400 kilometres from the Pamirs to the Aral Sea, and for most of recorded history the land on its two banks belonged to different worlds: Khurasan and the Iranian plateau to the south-west, and Transoxiana — the country the Arabic geographers called Mā warāʾ al-nahr, "what lies beyond the river" — to the north-east.
The archive uses the term deliberately and loosely. Alp Arslan, the Seljuk sultan who had beaten the Byzantine emperor at Manzikert the year before, was mortally wounded on campaign beyond this river in 1072, and the sources do not allow the spot to be fixed more precisely than that.
The Amu Darya rises in the Pamirs, formed by the junction of the Panj and the Vakhsh near Lake Zorkul at about 4,130 metres, and flows north-west across Central Asia. The classical name Oxus derives from Vakhsh, the larger of its two head-streams; medieval Islamic writers called it the Jayhūn, after the Gihon of Eden; and its modern name comes from the medieval city of Āmul on its bank, now Türkmenabat, with the Persian daryā, "sea".
It is a big, silty, fast river running through desert, and it could not be casually forded. Traffic crossed at established points — Termez upstream, Āmul in the middle course — where ferries and caravan routes concentrated. Those crossings carried the southern arm of the silk routes, and controlling them was worth more than controlling a great deal of the land on either side.
In the Iranian tradition the Oxus divided Iran from Tūrān, the settled world from the nomad one, and Arabic geographers took the same view: this was the edge of the ordered Islamic lands, beyond which lay the Turkish steppe. The distinction was never quite true — Transoxiana held Samarkand and Bukhara, two of the greatest cities of the Islamic world — but it shaped how people wrote about the region and how rulers thought about it.
For the Seljuks the frontier was personal rather than theoretical. They were themselves Turks from beyond the river who had taken Khurasan and then Iran and Iraq, and the Karakhanid rulers on the far bank were their kin and their rivals. A sultan crossing the Oxus eastwards in the eleventh century was going back towards the country his family came from.
In 1072 Alp Arslan took a large army east against the Karakhanids. The immediate cause given in the sources is a family quarrel — the killing of a close female relative by his son-in-law Shams al-Mulk Nasr — but the strategic point was control of Transoxiana. Crossing the river required boats to be built and a passage that the sources describe as taking weeks.
On the far side he besieged a fortress whose name is given as Barzam or Berzem, and whose site cannot now be identified on the ground. Its commander, named in the sources as Yusuf al-Khwarazmi, surrendered and was brought before the sultan; the interview went badly, Yusuf was condemned, and he rushed the throne with a dagger. Alp Arslan, an archer of great reputation, tried to shoot him, missed — the sources say his foot slipped — and took the blade in the body.
He lived a few days after the wound. The date of his death is not agreed: it is given as 24 November 1072 and also as 15 December, and the discrepancy runs through the modern literature as well as the medieval. He was about forty-three. He was carried back and buried at Merv, beside his father, and his son Malik-Shah I succeeded to an empire at its height.
The sequence is worth stating plainly because of how it is usually told. The victor of Manzikert did not die in Anatolia, in the war that made his name, but on the far side of the Oxus a year later, stabbed by a prisoner during a siege in a campaign nobody remembers. The account rests chiefly on Ibn al-Athir and the later Persian and Arabic historians, writing well after the event, and the precise place and day are beyond recovery.