Pir is a Persian word meaning spiritual guide. A pir has many synonyms, such as, Walis, Imamjadas, Shaikhs, which are current in Syria, Egypt and in North Africa. A sufi is also sometimes called pir, though all pirs are not sufis. As a religious institution, pirism was introduced in Bengal during the Sultanate. Appellations, such as fakir, mostan, shah, murshid, etc are synonymous to 'pir'. Pirs and sufis played pivotal role in propagating islam in Bengal.

Ordinary people are traditionally inclined to believe that pirs possess spiritual knowledge and are endowed with supernatural powers. They believe that pirs can transfer spiritual insight to their devoted followers and make their lives happy both before and after death. Pirs are said to have powers to solve the problems of the people in distress and help them in getting over their mundane problems. Through pirs people expect to come closer to Allah.

Socially, some pirs are seen to sustain their influence both during their lifetime and after their death. Their tombs are turned into dargahs for holding urs to mark their death anniversary and other events, including feasts and fairs. Devotees visit the mazars of pirs and pray for the salvage of the departed souls and for the fulfillment of their worldly wishes.

A large number of important mazars are located at different places of Bangladesh and many among them are popular sites for visitors and devotees. Among these great mazars are shrines of shah jalal (R) and shah paran (R) in Sylhet, bayazid bostami and shah amanat (R) in Chittagong, baba adam shahid in Munshiganj, shah ali baghdadi (R) in Mirpur, shah sultan rumi (R) in Netrokona, Shahid Shahdowla in Shajadpur, Ismail Ghazi in Dinanjpur, and khan jahan in Bagerhat. These historical pirs and dervishes came to Bengal over the centuries since the establishment of Muslim kingdom in this part of the world.

In addition to historically authenticated pirs, there are many folk-pirs who appear to be more mythical than real. Some of them are believed to be semi-historical, such as, Hawa Bibi, Khowaj Khijir, Trinath Pir Pouranik, Badar Pir, Mathar Pir, and Panch Pir while others are legendary, such as Satyapir, Ghazi Pir, Manik Pir, Sona Pir, Ban Bibi, Ola Bibi, Jangli Pir, and Monai Pir. The folk pirs exist not only in human form but also in the form of animals or birds, and even as material objects. Examples of non-human folk pirs are Ghora Pir, Kauwa Pir, and Nora Pir. According to folk belief, there are individual pirs who possess control over specific beings, living or non-living. For example, pirs like Khowaj Khijir has control over water, Badar Pir over boat, Mathar Pir over fire, Monai Pir over child, Manik Pir and Shona Pir over livestock, Ghazi Pir over tiger, Ban Bibi over forest, and Ola Bibi over Cholera. Believers in their powers make manat or offering in the form of shirni and other means to get relief from particular danger or dangers.

The Hindu community of Bengal practices offering shirni to relevant folk. At folk level sometimes inter religious practises towards the supernatural merge together to a large extent. For example, Satyapir is the Muslim version of Satyanarayan. Similarly, Ghazi Pir is that of Dakkhina Roy, Manik Pir of Gorakkhanath, Ban Bibi of Ban Durga, and Ola Bibi of Ola Devi. Ordinary people of lower social standing being deprived of education and enlightenment tend to rely on supernatural powers of living or dead pirs. Even many educated people are prone to visit shrines of folk pirs.

Some folk pirs are venerable to both Muslims and Hindus. For example, vows and shirnis are offered to both Ban Bibi and Ban Durga by all who enter the sundarbans for collection of timber, honey or tree leaves or, for fishing. Both Muslim and Hindu boatmen invoke the blessings of Badar Pir before they set out in a big river or in the sea. In the rural areas of Mymensingh, as well as in some towns, people throw food for kauwas (crows) to eat, which is a practice emanating from the belief in the powers of the Kauwa Pir. The tradition of sacrificing toy ghora (horse, made of earth) to satisfy Ghora Pir still prevails in many parts of Bangladesh.

Considering the importance of folk pirs and the rites and rituals associated with belief in them, scholars brand such traditional beliefs and practices as folk affair essentially. There are many folk-tales about the miracles demonstrated by Muslim and Hindu saints. Based on them have been created many popular literary works, such as Satyapirer Panchali, Ghazi-Kalu Champabati, and Ban Bibir Jahurnama. [Wakil Ahmed]