In the beginning of the 11th century, India was attacked by the Turks under the leadership of Mahmud Ghazni, the ruler of the Ghazni dynasty. The information about the Turk invasion comes from Firdausi’s composition ‘Shahnama’. ‘Shahnama’ is the first most famous work of Persian literature. Mahmud Ghazni of the Yamini dynasty, who was the son of Subuktagin, assumed the title of ‘Ghazi’. Mahmud Ghazni first attacked Jaipal, the ruler of the Hindushahi dynasty of Udbhandpur in 1001 AD. After that, in 1011-12 AD, the Chakraswami temple of Thaneshwar was attacked and in 1021-22 AD, Punjab was attacked. The basic objective of the invasion of Punjab was to establish a military centre. In 1025-26 AD attacked Somnath temple of Gujarat. The last invasion of Ghazni was against the Jat rulers in 1027 AD. The main objective of Ghazni’s invasion was to plunder money. Therefore, this invasion did not have a special impact on the political history of India and Bihar.
In the second half of the 12th century, Muhammad Ghori’s invasion of India began, which is also called the second phase of the Ottoman invasion. The original name of Muhammad Ghori was Moizuddin Muhammad bin Sham. It attacked India several times from 1175 AD to 1194 AD. The main objective of its attack was to establish political power and in this objective it was completely successful. Its invasion affected the area up to Bihar and Bengal in eastern India. The reason for its success was the lack of political unity. Like India, decentralized powers were dominant over Bihar at the time of its invasion. Bihar was also not an organized political unit. At this time, most parts of northern Bihar were ruled by the Karnat dynasty, while small states were established in other parts. At this time the rulers of the Sen dynasty of Bengal attacked Bihar and made its condition very pathetic.
Bakhtiyar Khilji first conquered Odantapuri (Biharsharif) in Bihar in 1198 AD and destroyed the educational institute Nalanda University established there. _ Three generals of Muhammad Ghori were campaigning in India, in which one of the generals Ikhtiyar-al-Din Muhammad bin Bakhtiyar Khilji was campaigning in eastern India till Bihar-Bengal. Bakhtiyar Khilji is also known as Ghazi Ikhtiar. Therefore, the credit for the establishment of Turkic power in Bihar goes to Bakhtiyar Khilji. At the time when Bakhtiyar Khilji invaded the Bihar-Bengal region, Lakshman Sen, the ruler of the Sen dynasty and Indradyumna Pal, the ruler of the Pala dynasty, opposed him. Bakhtiyar Khilji first conquered Odantapuri (Biharsharif) in Bihar in 1198 AD and destroyed the educational institute Nalanda University established there. After this 1203-04 AD. attacked Nadia, the capital of Lakshmana Sen and defeated him. Bakhtiyar Khilji conquered the regions of Bihar and Bengal and organized them into a province and established Lakhnauti as the capital. Bakhtiyar Khilji was assassinated by Alimardan Khilji in 1206 AD. After Bakhtiyar Khilji, the rule of Qutubuddin Aibak, another general of Muhammad Ghori, was established in this area. After the death of Muhammad Ghori in 1206 AD, Qutbuddin Aibak established an independent Ottoman power in Delhi, which is known as the Delhi Sultanate. The region of Bihar-Bengal also came directly or indirectly under the Delhi Sultanate after the death of Bakhtiyar Khilji. The establishment of the Delhi Sultanate marked the end of the early medieval period and the beginning of the medieval period. Which is known as Delhi Sultanate. The region of Bihar-Bengal also came directly or indirectly under the Delhi Sultanate after the death of Bakhtiyar Khilji. The establishment of the Delhi Sultanate marked the end of the early medieval period and the beginning of the medieval period.