Prithviraj Chauhan, also known as Rai Pithaura and Prithviraja, ruled Ajmer prior to Muslim conquest of Delhi.
The first battle at Tarain was fought between the Rajputs, led by Prithviraj Chauhan, and the Turks, led by Shahab-ud-din Muhammad Ghori, also known as Muiz-ud-din Muhammad Bin Sam (r: 1173-1206), the ruler of Ghazni, in 1191.
First Battle of Tarain (1191):
In 1191, during his eighth expedition to Hindustan, Muhammad Ghori marched from Ghazni and conquered the fort of Sirhind (Tabarhindh or Bathinda, according to various authors), and placed under the charge of Malik Zia-ud-din Kazi Tolak. Upon hearing this news, Prithviraj Chauhan advanced towards the Turks with a massive army consisting of cavalry, foot and elephants.
Ghori ordered Tulaki to hold the fort for eight months, until his return from Ghazni. However, on his way back, Ghori learned that 'Rai Pithaura, along with his brother Govind Rai and other Hindu Rajas, were marching towards Sirhind'. Ghori decided to return to the fort's relief.
The two armies met at the village of Tarain, on the banks of the river Sarsuti, in Haryana. When the fighting became intense, the Muslims' right and left wings were broken, and they fled, leaving their leader with the center. Ghori was advised by a faithful servant to provide for his own safety. But Ghori took his spear and charged towards the Hindus. He came to the elephants and pierced one of them in the shoulder.
Govind Rai, the Raja of Delhi, was leading the Hindu vanguard on an elephant. When he saw Ghori, he drove his elephant towards him. Ghori, rising from his horse, drove his lance into Govind Rai's mouth, causing him to lose two of his teeth. The Rai throw a spear that severely injured Ghori's upper arm, almost causing him to fall from his horse.
According to most Persian accounts, during this time, a Khilji soldier recognized Ghori, who mounted behind him, and supporting him in his arms, rode out of the battle field. The disappearance of Ghori caused chaos and confusion among his troops, ultimately leading to their defeat and flight. However, some of Ghori's chiefs spotted him being carried by the Khilji soldier and quickly gathered around him. They then carried him in a litter towards Ghazni.
In Al-Kamil fil-Tarikh, there are two different accounts of this campaign. According to one, Ghori was struck on his left arm and head, causing him to fall to the ground. Night separated the two sides and the Hindus retired. In the darkness, Ghori stumbled upon a group of his Turkish slaves who were searching for him among the corpses and weeping. Despite his excruciating pain, Ghori called out to them and they rushed to his aid. They carried him on their shoulders, taking turns until they reached Uch.
The second account seems to be more reliable. Ghori fell from his horse and his men fought around him to protect him from the Hindu forces who were determined to capture him, and 'the fighting over him was like nothing ever heard of'. After a long and brutal struggle, some of Ghori's men were able to lift him onto his horse and retreat from the battlefield. The Hindus did not pursue them. However, Ghori fainted from his injuries after traveling a league and his men carried him in a litter on their backs towards Lahore.
Meanwhile, Prithviraj Chauhan and his allies continued their march to Sirhind, where they laid siege to the fort for thirteen months and took it.
Ghori remained at Lahore until his wound was healed before returning to Ghazni. Once his troops were reunited, he disgraced the Ghurid amirs who had fled, and ordered them to parade around the city with their horse's mouth-bags filled with barley, which hung around their necks. He then made them swear an oath that they would consume the barley or face the consequences of having their heads severed. The amirs had no other choice.
Many sources document that Govind Rai, the Raja of Delhi, was the brother of Prithviraj.