The origin of the name Iban is a mystery, although many theories exist. During the British colonial era, the Ibans were called Sea Dayaks. Some believe that the word Iban was an ancient original Iban word for people or man. The modern-day Iban word for people or man is mensia, a totaly modified Malay loan word of the same meaning (manusia) of Sanskrit Root.
The Ibans were the original inhabitants of Borneo Island. Like the other Dayak tribes, they were originally farmers, hunters, and gatherers. Not much is known about Iban people before the arrival of the Western expeditions to Asia. Nothing was ever recorded by any voyagers about them.
The Ibans were unfortunately branded for being pioneers of headhunting. Headhunting among the Ibans is believed to have started when the lands occupied by the Ibans became over-populated. In those days, before the arrival of western civilization, intruding on lands belonging to other tribes resulted in death. Confrontation was the only way of survival.
In those days, the way of war was the only way that any Dayak tribe could achieve prosperity and fortune. Dayak warfare was brutal and bloody, to the point of ethnic cleansing. Many extinct tribes, such as the Seru and Bliun, are believed to have been assimilated or wiped out by the Ibans. Tribes like the Bukitan, who were the original inhabitants of Saribas, are believed to have been assimilated or forced northwards as far as Bintulu by the Ibans. The Ukits were also believed to have been nearly wiped out by the Ibans.
The Ibans started moving to areas in what is today’s Sarawak around the 15th century. After an initial phase of colonising and settling the river valleys, displacing or absorbing the local tribes, a phase of internecine warfare began. Local leaders were forced to resist the tax collectors of the sultans of Brunei. At the same time, Malay influence was felt, and Iban leaders began to be known by Malay titles such as Datu (Datuk), Nakhoda and Orang Kaya.
In later years, the Iban encountered the Bajau and Illanun, coming in galleys from the Philippines. These were seafaring tribes who came plundering throughout Borneo. However, the Ibans feared no tribe, and fought the Bajaus and Illanuns. One famous Iban legendary figure known as Lebor Menoa from Entanak, near modern-day Betong, fought and successfully defeated the Bajaus and Illanuns. It is likely that the Ibans learned seafaring skills from the Bajau and the Illanun, using these skills to plunder other tribes living in coastal areas, such as the Melanaus and the Selakos. This is evident with the existence of the seldom-used Iban boat with sail, called the bandung. This may also be one of the reasons James Brooke, who arrived in Sarawak around 1838, called the Ibans Sea Dayaks. For more than a century, the Ibans were known as Sea Dayaks to Westerners.