Areas comprising what is now Brunei participated in the Maritime Jade Road, as ascertained by archeological research. The trading network existed for 3,000 years, between 2000 BC to 1000 AD.[28][29][30][31] The settlement known as Vijayapura was a vassal-state to the Buddhist Srivijaya empire and was thought to be located in Borneo's Northwest which flourished in the 7th Century.[32] Vijayapura itself upon earlier in its history, was a rump state of the fallen multi-ethnic: Austronesian, Austroasiatic and Indian, Funan Civilization; previously located in what is now Cambodia.[33]: 36 This alternative Srivijaya known as Vijayapura referring to Brunei, was known to Arabic sources as "Sribuza".[34]
One of the earliest Chinese records of an independent kingdom in Borneo is the 977 AD letter to the Chinese emperor from the ruler of Boni, which some scholars believe to refer to Borneo.[35] The Bruneians regained their independence from Srivijaya due to the onset of a Javanese-Sumatran war.[36] In 1225, the Chinese official Zhao Rukuo reported that Boni had 100 warships to protect its trade, and that there was great wealth in the kingdom.[37] Marco Polo suggested in his memoirs that the Great Khan or the ruler of the Mongol Empire, attempted and failed many times in invading "Great Java" which was the European name for Bruneian controlled Borneo.[38][additional citation(s) needed]
According to Wang Zhenping, in the 1300s, the Yuan Dade nanhai zhi or "Yuan dynasty Dade period southern sea records" reported that Brunei or administered Sarawak and Sabah as well as the Philippine kingdoms of Butuan, Sulu, Ma-i (Mindoro), Malilu 麻裏蘆 (Manila), Shahuchong 沙胡重 (Siocon or Zamboanga), Yachen 啞陳 Oton, and 文杜陵 Wenduling (Mindanao),[39] which would regain their independence at a later date.[40]
In the 14th century, the Javanese manuscript Nagarakretagama, written by Prapanca in 1365, mentioned Barune as the constituent state of Hindu Majapahit,[41] which had to make an annual tribute of 40 katis of camphor. In 1369, Sulu which was also formerly part of Majapahit, had successfully rebelled and then attacked Boni, and had invaded the Northeast Coast of Borneo[42] and afterwards had looted the capital of its treasure and gold including sacking two sacred pearls. A fleet from Majapahit succeeded in driving away the Sulus, but Boni was left weaker after the attack.[43] A Chinese report from 1371 described Boni as poor and totally controlled by Majapahit.[44] When the Chinese admiral Zheng He visited the Brunei in the early 15th century, he founded a major trading port which included Chinese people who were actively trading with China.[45]
During the 15th century, Boni had seceded from Majapahit and then converted to Islam. Thus transforming into the independent Sultanate of Brunei. Brunei became a Hashemite state when she allowed the Arab Emir of Mecca, Sharif Ali, to become her third sultan.
As customary for close affiliation and alliances in Southeast Asia, the royal family of Luzon intermarried with the ruling houses of the Sultanate of Brunei.[46] Intermarriage was a common strategy for Southeast Asian states to extend their influence.[47] However, Islamic Brunei's power was not uncontested in Borneo since it had a Hindu rival in a state founded by Indians called Kutai in the south which they overpowered but didn't destroy.
Nevertheless, by the 16th century, Islam was firmly rooted in Brunei, and the country had built one of its biggest mosques. In 1578, Alonso Beltrán, a Spanish traveller, described it as being five stories tall and built on the water.[48]