Pashtuns in the armies of Sultan Shahabuddin Ghori and Prithviraj

According to Gulshan-i-Ibrahimi (written in 1612 AD), Afghans (Pashtuns) and Khaljis formed the vanguard of the army of Sultan Shahabuddin Ghori. The Pashtun and Khalji commanders of the vanguard (مقدمة الجیش), who always boasted of their valour and prowess, fled from the battlefield (along with the right and left wings of the army) in the first battle of Tarain (1191), leaving the Sultan with the centre of Army (لشكر قلب).

Another interesting detail from Gulshan-i-Ibrahimi (or Tarikh-i-Farishta) is that after the defeat in the first battle of Tarain, Sultan Shahabuddin severely punished and humiliated his nobles from Khalj, Ghor and Khorasan who fled the battlefield, but he spared Afghan (Pashtun) Amirs out of prudence. 

In the second battle of Tarain (1192 AD), the 107,000 strong army of Sultan Shahabuddin of Ghor was comprised of Turks, Tajiks and Afghans (Pashtuns).

The 300,000 strong cavalry of Rai Pithora (Prithviraj) in the second battle of Tarain (1192 AD), was comprised of Rajputs and Afghans (Pashtuns).

So Pashtuns were fighting on both sides. For this reason, Sultan Shahabuddin exercised caution in his dealings with his Pashtun amirs. He did not punish and humiliate Afghan (Pashtun) amirs for fleeing from the battlefield in the First battle of Tarain, perhaps fearing that the latter may switch allegiance to Rai Pithora. 

The above snippets are taken from an Urdu translation of Gulshan-i-Ibrahimi (popularly known as Tarikh-i-Farishta). Its author Muḥammad Qasim Hindu Shah was born in Astarabad in northern Persia around 1550 AD. Farishta was his pen name.

A thirteenth-century description of Pashtuns

Pashtuns appeared as a strange, novel and fearsome body of people to Minhaj al-Siraj Juzjani, the author of Tabaqat-i-Nasiri who was born in the Ghurid capital city of Firuzkuh and passed his childhood in the harem of a Ghurid princess. He gives the awe-struck description of Pashtun soldiers in the service of Ulugh Khan (the future Sultan Balban) as follow:- 

 "The defenders of truth, in conformity with Ulugh Khan-i-Azam's commands, penetrated into all the loftiest places, into the defiles, and deep ravines, and acquired heads and captives, and became filled with property and money, especially the sept of Afghans, every one of whom you might say was some huge elephant with [the tails of] two Khita-i bulls over his shoulders, or some tall tower of a fortress, placed on its summit, for the purpose of over-awing, with banner displayed. The number of them, employed in the service of, and attending the stirrup of, Ulugh Khan-i-Azam, was about 3,000 horse and foot, daring, intrepid, and valiant soldiers, each one of whom, either on mountain or in forest, would take a hundred Hindus in his grip, and, in a dark night, would reduce a demon to helplessness." (Tabaqat-i-Nasiri, English translation by H.G.Raverty, Vol-2, p-852) 

 Original Farsi text of the above passage from Tabaqat-i-Nasiri (edited by Abdul Hai Habibi) :-

Tajiks

A Turkic runic inscription in Southern Kazakhstan dating to 720 AD, refers to Arab invaders as "Taziks" (Tajiks)

The term Tazik or Tajik was originally applied to Arabs or their descendants in Ajam. The author of Hayat-i-Afghani says : "Of the many theories regarding the etymology of this word Tajik, the most probable is that which makes it a corrupt form of the Pahlvi word, Tazi, an Arab, a word still current in modern Persian with the same meaning. All the dictionaries give Tazi as meaning the descendants of Arabs in Persia or any other foreign country." 

Note that Ghorids were not Tajiks in the meaning of Farsiwan. They are called Tajiks because they claimed to be descendants of Zahhak, an evil Arab king of Persian mythology who had serpents growing out of his shoulders.