Oghuz expansion by means of military campaigns went at least as far as the Volga River and Ural Mountains, but the geographic limits of their dominance fluctuated in the steppe areas extending north and west from the Aral Sea.

Accounts of Arab geographers and travelers portray the Oghuz ethnic group as lacking centralized authority and being governed by a number of "kings" and "chieftains."

Because of their disparate nature as a polity and the vastness of their domains, Oghuz tribes rarely acted in concert. Hence,

by the late 10th century, the bonds of their confederation began to loosen. At that time, a clan leader named Seljuk founded a dynasty and the empire that bore his name on the basis of those Oghuz elements that had migrated southward into present-day Turkmenistan and Iran.

The Seljuk Empire was centered in Persia, from which

Oghuz groups

spread

into Azerbaijan and Anatolia.

After the fall of Göktürk kingdom, Oghuz tribes migrated to the area of Transoxiana, in western Turkestan, in modern Kazakhstan and Kirghizstan. This land became known as the "Oghuz steppe" which is an area between the Caspian and Aral Seas.

Ibn al-Athir,

an Arab historian,

stated that the

Oghuz Turks had come to Transoxiana in the period of the caliph Al-Mahdi in the years between 775 and 785.

[[[ Athir --- Athur --- Arhur (???)]]]

In the period of the Abbasid caliph Al-Ma'mun (813-833), the name Oghuz starts to appear in the Islamic historiography. By 780 AD, the eastern parts of the Syr Darya were ruled by the Karluk Turks and the western region (Oghuz steppe) was ruled by the Oghuz Turks.

The name Turkmen first appears in written sources of the

10th century to distinguish those

Oghuz groups who migrated south into the Seljuk domains and accepted Islam from those that had remained in the steppe. Gradually, the term took on the properties of an ethnonym and was used exclusively to designate Muslim Oghuz, especially those who migrated away from the Syrdariya Basin. By the 13th century, the term Turkmen supplanted the designation Oghuz altogether. The origin of the word Turkmen remains unclear. According to popular etymologies as old as the 11th century, the word derives from Turk plus the Iranian element manand, and means "resembling a Turk." Modern scholars, on the other hand, have proposed that the element man /men acts as an intensifier and have translated the word as "pure Turk" or "most Turk-like of the Turks."

Seljuks

In the 11th century, Seljuk domains stretched from the delta of the Amu Darya delta into Iran, Iraq, the Caucasus region, Syria, and Asia Minor. In 1040 the Seljuk Turks crossed the Oxus from the north, and having defeated Masud, sultan of Ghazni, raised Toghrul Beg, grandson of Seljuk, to the throne of Iran, founding the Seljukid dynasty, with its capital at Nishapur. A younger brother of Toghrul, Daud, took possession of Merv and Herat. Toghrul was succeeded by his nephew Alp Arslan (the Great Lion), who was buried at Merv. It was about this time that Merv reached the zenith of her glory. In 1055 Seljuk forces entered Baghdad, becoming masters of the Islamic heartlands and important patrons of Islamic institutions. Until these revolts, Turkmen tribesmen were an integral part of the Seljuk military forces. Turkmen migrated with their families and possessions on Seljuk campaigns into Azerbaijan and Anatolia, a process that began the Turkification of these areas. During this time, Turkmen also began to settle the area of present-day Turkmenistan. Prior to the Turkmen habitation, most of this desert had been uninhabited, while the more habitable areas along the Caspian Sea, Kopetdag Mountains, Amu Darya, and Murgap River (Murgap Deryasy) were populated predominantly by Iranians.

The city-state of

Merv

was an especially large sedentary and agricultural area, important as both a regional economic-cultural center and a transit hub on the Silk Road.

The last powerful Seljuk ruler, Sultan Sanjar (d. 1157), witnessed the fragmentation and destruction of the empire because of attacks by Turkmen and other tribes. During the reign of Sultan Sanjar or Sinjar of the same house,

in the middle of the 11th century,

Merv

was overrun by the Turkish tribes of the Ghuzz from beyond the Oxus. It eventually passed under the sway of the rulers of Khwarizm (Khiva). After mixing with the settled peoples in Turkmenistan, the Oguz living north of the Kopet-Dag Mountains gradually became known as the Turkmen.

The Seljuk empire broke down in the second half of the 12th century, and the Turkmen became independent tribal federation.

Mongols and Timurids

In 1157, the rule of Seljuks dynasty came to an end in the province of Khorasan. The Turkic rulers of Khiva took control of the area of Turkmenistan, under the title of Khwarezmshahs in 1221, central Asia suffered a disastrous invasion by Mongol warriors who swept across the region from their base in eastern Asia."

"Under their commander,

Genghis Khan, founder of the Mongol Empire, the Mongols conquered Khwarezm and

burned the city of Merv to the ground.

The Mongol leader ordered

the massacre of Merv's inhabitants

as well as

the destruction of the province's farms and irrigation works

which effectively ended the Iranian dominance in urban areas and agricultural communities of khwarezm.

These areas were soon repopulated by the Turkmen who survived the invasion and had retreated northward to the plains of Kazakhstan or westward to the shores of the Caspian Sea. After the division of the Mongol Empire, present Turkmenistan was passed to Chagatai Khanate except southernmost part was belonged to Ilkhanate.

Small, semi-independent states arose under the rule of the region's tribal chiefs later in the 14th century.

In the 1370s, Amir Timur (also known as Tamerlane), one of the greatest conquerors in human history, captured Turkmen states once more and established the short lived Timurid Empire, which collapsed after Timur's death in 1405, when Turkmens became independent once again."

(from Wikipedia)

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So, we are looking for a possibilty English/British Wizard Merlin had came on island England as a traveler Wizard from a town Merv.

Merv ----- Merlin (???)

We will see events in Merv town history:

https://en.wikipedia.org/wiki/Merv

From Wikipedia