For more than two millennia, Indian sub-continent has suffered one bloody invasion after another, leaving a Holocaust of millions of lives and a civilization and culture left in near ruins. Many foreign invaders & conquerors ruled Bengal as well as the Indus valley. They snatched away our wealth, made us slaves, occupied us or lived with us. Some of them came to robbery, some of them to missionary, some to rule or to preach. Some foreign nations mixed with sub-continental people in blood, culture & manner or we mixed with them. Shortly here are given below the intruders and conquerors of our land in serial from the very ancient age.
• Alexander & the Greeks
• The Aryans
• The Mauryan Empire
• Shunga Dynasty
• Shatavahana Empire
• Kushan Empire
• Gupta Dynasty
• The Rajputs
• Vijaynagar Empire
• Arab & Turkish invasions
• The Mamluk (Slave) Dynasty
• Delhi Sultanante
• Pala Dynasty
• Sena Dynasty
• Khilji Dynasty
• The Tughlakhs
• Sayyid & Ludi Dynasties
• The Mughals
• British rule
• Under Pakistan
For the long period of time, we were occupied and ruled by these nations & dynasties. They burdened us with their religion, beliefs & culture. Some preaches their ideologies and tried to obtain the land. Bakhtiyar Khilji’s intrusion was one kind of them.

Social & cultural condition of Bangla in different age:

 Vedic Civilization:
Vedic civilization is the earliest civilization in Indian history. It is named after the Vedas, the early literature of the Hindu people. This civilization is the foundation of Hinduism and the associated Indian culture that is known today. The Aryans oppressed on the local people too much. They made them slaves, burdened with Veda and Sanskrit. At first there was no caste system, but with the passage of time they made the caste system and the oppressive Brahmanism. Only Aryans could be Brahmin, Khatriya & Vaishya. But local people only regarded as Shudra.

 Maurya Dynasty:
As Asoka became a devout Buddhist, he began to spread the teachings of Buddha by issuing edicts. These edicts were sent to different parts of the empire, where they were engraved on rocks or pillars, for the common people to see and read them. These edicts were written in different scripts. Most of them were in Brahmi, which was common in most parts of the empire. The language was generally Prakrit (ancient language), as it was spoken by the common people, whereas Sanskrit was spoken by educated upper caste people.

 Gupta Dynasty:
The Gupta emperors were Brahmins. So they revived Hinduism & caste system. But they were kind enough to their subjects.

 Pala Dynasty:
Pala kings were Buddhists. They were too kind and benevolent. They ushered a period of relative stability and prosperity.

 Sena Dynasty:
Sena kings were the followers of Brahmanism. They again revived the caste system and the period of oppression. The lives of the common people, rich or poor, during the reign of the Sena Kings were not happy. The main power was in the hands of the upper class (the Brahmins). The practice of the knowledge of the scripture was limited among the Brahmins only. The persecution by the Brahmins made the lives of the common people miserable. This persecution was inflicted mostly upon the Buddhists. The Brahmins used to snatch away their wealth. They were not punished if they killed the Buddhists. Towards the end of the Sena rule, the common people became aggrieved due to the oppression of the kings. It is known that Ballava, the Queen of Lakhshan Sena and her brother, Kumara Dutta used to torture the common people too much. The degree of torture was so great that even the courtiers of the Royal Court, resented along with the common people.

 Khilji Dynasty:
The Medieval Age in Bengal began with the assumption of power by the Muslims. Before the advent of the Muslims, people belonging to the Hindu and the Buddhist religions lived in Bengal. The Muslims under the leadership of Bakhtiar Khilji entered Bengal as a royal power in the beginning of the thirteenth century. Even five to six hundred years before that the Arab Muslims who had come to do business were living on the coastal belt in Southeast Bengal. The Sufis and the Saints began to come to Bengal to preach Islam from the eleventh century. Many of the common Hindus and Buddhists embraced Islam at the time. Thus, gradually a Muslim social structure developed in Bengal. The Hindus and the Muslims lived side by side all over Bengal at the time. As a result, a sort of mixture began to take place between one another's thoughts and rituals. The culture which evolved in this way is called the Bengali culture.

Why this change was needed:

During the Senas’ rule, there was a revival of Brahmanism, specifically Kulinism, and, gradually, Buddhism lost its prominence. Under the Brahmanic influence, society became more stratified and caste conscious with the Brahmins residing at the top of the class hierarchy. Though Lakhshan Sena was famous with kindness & literary, people were fed up with the system.
Bakhtiyar Kilji, a general of Sultan Kutubuddin Ibeq, suddenly attacked Bangla and obtained Nadia with only seventeen men and then Lakhnauti. Thus Islam got political establishment in Bangla. Most of the history writers presented Bakhtiyar as a symbol of destroys although.

Bakhtiyar was a good administrator. He divided the kingdom into a number of districts and assigned them to the care of his principal nobles and military chiefs. They were entrusted with the duty of maintaining peace and order, collecting revenues, patronising learning and culture and looking after the moral and material well being of the people. Following the traditional principle he took steps to read the Khutbah and to introduce coins in his name. He established two cantonment towns near Dinajpur and Rangpur. He built numerous mosques, madrasas and khanqahs. Though he was a intruder, people embraced his rule and religion.

If we analyze the motif behind the advent of Bakhtiyar Khilji in Bangla, we can easily find out that he had the greater intention in obtaining lands, not to preach Islam. As a Muslim, he did the same things as other Sultans. Besides, Islam was being preached in Bangla century before his come. But the thing is that, by the means of his intrusion, Islam established politically and people got the touch of Islam. They freely got to know about Islam and saw the beauty of Islam. Islam is surely a way of life, religion of equality and loving each other. So, it is the Islam, which drove away all discrimination and built a worth culture of kindness & tranquility. That’s why, at that time, this kind of advent was long awaited.