Composed of the present-day Indian district of Karimganj, as well as parts of Tripura State and Sylhet, Bangladesh, the kingdom was ruled by a line of Muslim monarchs over a mixed population of Hindu and Islamic adherents.

It is believed that during the latter years of the 15th century AD, the area was seceded by Malik Pratap, a landowner of mixed native and Persian ancestry, who established the kingdom and from whom it may have received its name.

However, the kingdom's legacy continued to have a notable impact in the region, with its name being borne by subsequent administrative divisions in the area and its history and legends surviving as oral traditions among the local population.

Originally called Sonai Kachanpur, the area was renamed Chatachura after the wandering Magadhan prince Chatra Singh, who received the land as a gift from the Maharaja of Tripura c. 1260 AD, about two hundred years prior to Pratapgarh's foundation.

[2][note 1] Incorporating dense, tiger-inhabited forests,[4][5] his territory stretched from Karimganj up to parts of the Lushai Hills and had its capital in Kanakpur, named after his son Kanak Singh.

[9] The earliest recorded member of the royal family of Pratapgarh was a Persian noble, Mirza Malik Muhammad Turani, who lived at the close of the 14th century AD.

Turani, as a result of family feuds in his native Iran, migrated to the Indian subcontinent with a large force, first going to Delhi before settling in present-day Karimganj district.

[9][12] Although by this point nearby Sylhet had long since been conquered for Islam by the warrior-saint Shah Jalal, the area to which Turani arrived was in the dominion of the Maharaja of Tripura, still under the control of Hindu tribes.

[14] According to the researcher Habib Ahmed Duttchowdhury, Turani is identical to the Timurid prince Muhammad Sultan Mirza, grandson of the Central Asian conqueror Timur.

While the Maharaja was distracted and lacked the means to intervene, Malik Pratap was said to have seceded Pratapgarh from Tripura's control (an area roughly equivalent to what is now Karimganj district) and declared himself its independent ruler.

[24] Hussain Shah, wishing to avoid war, sent one of his nobles, a recently converted Muslim from Sylhet named Surwar Khan, to negotiate with the Sultan of Pratapgarh.

[26][27] Hussain Shah agreed to allow Bazid to continue as ruler of Pratapgarh with relative independence, but he was required to surrender his control of Sylhet and give up the title of Sultan.

[23][28] However, Subir Kar, a professor at Assam University, identified the ruler as being the similarly-named Hussain Shah Sharqi of Jaunpur, with the described conflict instead taking place in 1464 AD.

Ali suggests that Bazid was identical to Bayazid of Sylhet, who was not subjugated by a reigning monarch, but rather by the Mughal governor of Bengal, Islam Khan I, in 1612 AD.

The surviving members of the royal family were forced to flee to their relatives in Jangalbari, located in modern-day Kishoreganj,[note 5] while Pratapgarh was incorporated into the Kachari Kingdom.

The head of the former royal family at this point was a nephew of the old Raja, Sultan Muhammad, who was nicknamed "Ranga Thakur" (the Scarlet Lord) and was famous for his physical beauty.

[43] As with neighbouring Sylhet, the inhabitants speak a common dialect of Bengali known as Sylheti, with the region as a whole, in the words of historian Jayanta Bhattacharjee, being "geographically, historically and ethnically an extension of Gangetic Bengal".

[2][45] The Khasi people have also maintained a presence and though Pura Raja had been their last important chief,[46] the chronicler Mirza Nathan notes in his Baharistan-i-Ghaibi that even in the 17th century AD, they enjoyed an essentially independent status in the kingdom.

[note 7] His maqam, which is located there, is venerated by timber merchants, Hindu and Muslim alike, with the lower-caste Hindus of Karimganj district as a whole also paying homage to him.