For centuries, the Iranun were involved in pirate-related occupations in the Malay world. Originally from the Sultanate of Maguindanao, in southern Mindanao, Illanun colonies spread to throughout Mindanao, the Sulu Archipelago and the north and east coast of Borneo. Most Illanun are Muslim. Their language is part of the Austronesian family, and is most closely related to Maranao of the Philippines. Its ISO code is ISO 639-3 ill. Historically, the Iranun were given the exonym Illanun during the British colonial era.
Iranun was one of the oldest existing nations in the world during the ancient times with definite integral territory wherein the sovereign power and authority was exercised over it by the legitimate ruler. Iranun as a nation inhabited mainly the Crab Gulf (Moro Gulf). Its villages were established and concentrated in the Iranun Bay (Illana Bay). The origin was attributed to the people of the Uranen Kingdom of the primitive past who inhabited in Tbok (Malabang). Iranuns were the first people who entered into a marriage affinity with Shariff Aulia and Shariff Kabunsuan. Bai sa Pandan (Princess Pagunguwan, daughter of Rajah Urangguwan) and Bai Angintabu respectively. Their wedlocks where Sultan Kudarat who directly got his line of descent from them. Iranun was a breed nation between the Karibang-Karingke Line of descent and last wave of Malay migrants. From this marriage affinity sprang the Iranun nation whose first leader was Rajah Urangguwan. The name of their place (state) was Uranen. During the advent of the Shariffs, union took its place in the kingdom through uninterrupted inter-marriages among the royals.
The language of the Maranao and Maguindanao in the Philippines is strongly rooted in the Iranun tongue. The Iranun may perhaps be the mother language and the rest are just a mere dialects. For several centuries, the Iranuns in the Philippines formed part of the Maguindanao sultanate. Their culture received much influence from the Maguindanaon rather than the Maranao. In the past, the seat of the Maguindanao sultanate was situated at Lamitan and Malabang. Both of which were the strongholds of the Iranun society. Iranuns fought the western invaders under the flag of the Maguindanao sultanate. The Iranun were excellent in maritime activity. They used to ply the route connecting the Sulu sea, Moro gulf to Celebes sea, and raided the Spanish held territories along the way.
The Iranun have also attained a degree of social organization comparable to the Maguindanao or the Tausug. This is evidenced by the datu system of leadership where a single leadership is recognized. An Iranun datu, like a sultan, wielded central power over his people. On account of their small population, the Iranuns have been overpowered by their neighbor and prevented them from having their own sultanate.