The Sultanate of Maguindanao, which once covered territory stretching from Lake Lanao to Sarangani Bay and centered in the Pulangi River area, was established by Sharif Kabungsuwan (Shariff Kabunsuan), who arrived in Mindanao in around 1515. His title of sharif indicates that he was a descendant of the Prophet Muhammad. By marrying a Sulu princess, he solidified his leadership of the Maguindanao area, albeit short of actually calling himself sultan, a contrast with neighboring Sulu. From its first ruler, Sultan Sharif ul-Hashim (Sayyid Abubakar Abirin or Zein ul-Abirin), the Sultanate of Sulu always had sultans at the helm. In fact, it was not until the reign of his grandson, Datu Bangkaya (Bancaya), would the title appear, but not in the Maguindanao tarsilas. It was from a Spanish report in 1579 which called Bangkaya as asulutan (as-sultan, an informal declension of sultan). Whether or not Bangkaya was also recognized as such in Maguindanao itself, it would be up to speculation. Still, this could be seen as an indicator of Maguindanao's growing influence. Meanwhile, upon learning Bangkaya's intent of friendship, the Spanish sent a mission to Maguindanao on March 13 of the same year. However, Bangkaya and his son, Datu Dimasangkay (Dimasancay), was nowhere to be found.

It is not that the Spanish failed to explore the Pulangi River, a 320 kilometer body of water flowing from Bukidnon to Cotabato. The Maguindanao leadership became cautious in actually dealing with the Spanish after learning of the military campaigns they conducted against other Muslim states such as Brunei (under Sultan Seif ur-Rijal or Saiful Rizal) and Sulu (under Sultan Muhammad ul-Halim or Pangiran Buddiman) in 1578. Meanwhile, it did not take long before Bangkaya and Dimasangkay passed away. There came to be an apparent power struggle, with Dimasangkay's half-brother Gugu Salikula gaining leadership of the Maguindanao datus by 1585. In his bid to power, Salikula reduced Dimasangkay's son, the rajah muda (crown prince or young ruler), as a figurehead, with himself holding the real authority despite having no title.

As for the Spanish, their victories against Brunei and Sulu bolstered their belief to further expand their influence in Mindanao. Their next target would be Maguindanao, but they would not find Salikula in power any longer. By 1596, when the Spanish force of 50 ships and 1,714 troops (214 of which were Spaniards) were dispatched under the command of Captain Esteban Rodriguez de Figueroa, Maguindanao was already under the leadership of Datu Buisan, also Dimasangkay's half-brother. While details on Salikula and Buisan's conflict were scant, it was apparent that Maguindanao was left in a weakened state over a decade of internal struggles. Figueroa, a veteran of the 1578 Brunei and Sulu campaigns, did not find the Maguindanao ruler, who had retreated deeper into Pulangi territory to avoid engagement. In his chase through the Pulangi, Figueroa managed to reach Buayan (now Datu Piang), where a relative of Rajah Sirungan (Sirongan) killed him. Figueroa's campaign lasted only five days. Still, the Spanish managed to establish a fort in Tampakan in the Cotabato area.

Undeterred by Figueroa's death, the Spanish sent another expedition under Juan Ronquillo in 1597 to save whatever gains were made the year prior. The retreat and return tactic was a trademark in Filipino military battles. It was more of brilliance than cowardice. By not engaging with Figueroa earlier, Buisan was able to conserve his forces to launch their own offensive. Teaming up with Sirungan, Buisan sought help from Sultan Saidi Berkat (Said Din Berkat) of Ternate to flush out the Spanish garrison at Tampakan. Ternate responded with a force of 800 warriors under the Sultan's uncle, Katchil Baba. However, the Muslim campaign failed. Despite this, Buisan did not give up on solidifying his alliance with Ternate by arranging a marriage between his nephew, the rajah muda, and Saidi Berkat's sister. While the Spanish tried to influence the process by proposing the sister of the Tampakan datu as an alternative, this intervention failed to materialize. By this time, the Spanish realized the paramount importance of securing Mindanao for further campaigns against the Dutch Moluccas. Then again, this was no easy task. Ronquillo reported some Muslim rulers having command of up to 6,000, and further commenting that this was larger than any one Luzon or Visayas ruler can exercise control over.

Meanwhile, Buisan believed in taking the fight away from home and into enemy territory. In 1599, Maguindanao and Buayan organized a fleet of 50 ships manned by 3,000 troops to raid the towns on Panay, Negros, and Cebu. This raid, known also as pangangayaw or mangayaw, was a display of military prowess. They managed to capture 800 captives. In 1600, they made another round of raids. While repulsed in Iloilo, they captured 800 more captives. This was not the end of the Muslims' naval campaigns, however. Two years later, Buisan himself led a fleet of 145 ships with Sirungan and Maguindanao's rajah muda to attack the Spanish settlements once more. The Spanish getting advanced intelligence of the massive force did not do much help. The fleet split itself into two, making it difficult for the Spanish to respond. Sirungan and the rajah muda went to Calamian (Palawan) while Buisan raided Mindoro and Batangas. Some 1,400 captives were gained. It was from this point that Kapitan Laut Buisan became a terror of Spanish controlled seas. His campaigns in Southern Luzon proved too close to the capital in Manila, and he was taking advantage of Spanish problems elsewhere. On December 14, 1600, the first of the Dutch naval offensives took place near Batangas, where the Spanish squadron under Antonio de Morga suffered defeat. Morga's flagship, San Diego, was sunk. This signalled the entry of the Philippines in the Eighty Years' War between the Netherlands and Spain.

Buisan's incursions into Spanish towns was part of a larger strategy - to convince the conquered peoples of Luzon and Visayas that they were not safer under Spain's suzerainty than they were otherwise, and to reinforce the message that overthrowing the Spanish yoke would mean having Buisan as their ally and friend. As for the Spanish, thinking that Buisan needs to be stopped, launched a counteroffensive also in 1602, but against Sulu. A force of 400 under Juan Gallinato attacked Jolo and laid siege further inland. It proved to be a tactical failure for no stronghold was created. The Spanish were forced to retreat after three months. However, the strategic objective of keeping Sulu away from Maguindanao's influence for a time was achieved. Then again, the Spanish miscalculated Sulu's importance on Buisan's campaigns. By taking out Sulu, Maguindanao was freed from its obligations to devote resources for its defense.

In 1603, another fleet of 50 ships under Kapitan Laut Buisan attacked Leyte. This led to the Leyte datus to form an alliance with him via sanduguan or blood compact, a symbolic ritual which became more iconic because it was done between Christianized and Muslim rulers. To make matters worse, Moro pirates, notably the Camucones of Tawi-Tawi, were also conducting their own raids in the wake of Buisan's destabilization work. With the Dutch threat, the Spanish could not hope to face military problems on so many sides. They need to at least neutralize Maguindanao if they were to focus on the Dutch campaign. Thus, in 1605, they entered into an agreement with Sirungan to recognize him as the paramount ruler of Maguindanao in exchange of his allegiance to Spain. By recognizing Sirungan, they were trying to create conflict between the Rajah of Buayan and Maguindanao's Kapitan Laut.

Mustering a fleet of 36 ships with more than 3,000 troops, the Spanish then proceeded to attack Ternate and the Dutch Moluccas under the command of the Governor General himself, Pedro de Acuña, but en route, they decided to stop over Maguindanao to meet the rulers there. None showed up, not even Sirungan, which somehow reminded of Datu Bangkaya's non-appearance decades earlier. They feared that one false move and the Spanish would turn against them. This also indicated that Sirungan did not fully trust the Spanish to honor their agreement. In fact, Sirungan did not get to finalize the agreement which was to be ratified in Manila. A victorious Spanish offensive sent shockwaves to Mindanao, for in 1606, Sirungan and Buisan asked the Spanish not to retaliate against them for their previous alliance with Ternate. The new governor general, Acuña's successor, gave them pardon. It was but a short peace, the agreement proving only to be a breather.

Another Muslim fleet composed of 67 ships under Buisan and the rajah muda raided Leyte and Samar in 1608. Notable was the absence of Sirungan, who actually went to Moluccas to negotiate with the Dutch. The Spanish were not having any more of it. The following year, Buisan's 60-ship fleet manned by 2,000 troops from Maguindanao and his allies in Caraga were cornered by Gallinato's forces at Panguil Bay. This forced Buisan to once again ask for peace, and this time, it was upheld for real. He must have also saw developments elsewhere, and it did not bode well for continued naval campaigns. In 1608, Sulu's Sultan Batara Shah Tengah, also Buisan's ally, sent an envoy to Manila to sue for peace and establish commercial relations. The Kapitan Laut made no major campaign against Spanish seas until his death in 1619. While Buisan's inactivity against Spain did not mean other Muslim rulers would stop their raids, this gave him leeway to focus into the mainland and expand his power in Pulangi. After all, the Spanish also halted further campaigns in Mindanao for the meantime due to the Dutch.

During the years of relative peace with the Spanish, Buisan made attempts to strengthen Maguindanao as it was weakened by Spanish campaigns against his allies like Sulu and Ternate. In the process, neighboring states like Buayan started to gravitate towards his leadership. The Dutch recognized this centralization of power under Buisan, and so they began discussions with him by 1614 to help in their campaign against Spain. By this time, the Dutch had already enlisted the cooperation of the new Sulu ruler, Sultan Muwallil Wasit (Rajah Bongsu), albeit the Dutch did not really send much assistance to Sulu anyway. Buisan might have saw this shallow alliance, and so he did not press the agreement further. Despite his ultimate loss at Panguil Bay, the Kapitan Laut's reign of two decades saw the foundations of the Maguindanao sultanate being built for his son, the famed Sultan Muhammad Dipatuan Kudarat (Corralat, Qudarat, Guserat). By the time Kudarat succeeded his father in 1619, both the Dutch and the Spanish were in talks with Maguindanao. This was a significant development, for until Buisan, it was usually expected that Maguindanao would only negotiate with one of them at a time, as exemplified by the adage, the enemy of my enemy is my friend. This was not entirely the case for Maguindanao diplomacy under the Kapitan Laut and his son. When the Dutch failed to aid Kudarat in his campaign, as they once did to Bongsu, he turned to the Spanish. This displayed such flexibility in their diplomatic relations. As for the story of Sultan Kudarat and how he became one of the great Muslim heroes of the Philippines, it would be best left for yet another article.

Buisan's uniqueness as Kapitan Laut was evident because virtually none among the neighboring Muslim states actually had an admiral to lead their fleets. For instance, Buayan in 1620 was requesting for a kapitan laut from Ternate because they had no one qualified to fill the position. Meanwhile, the 1613 raid of a certain Datu Pagdalanum against Samar and Leyte was done by a ragtag force from Maguindanao, Caraga, and Ternate. It was clearly not sanctioned by the Maguindanao sultanate, nor was the raid quite as large as Buisan's campaigns. Pagdalanum was only able to launch 30 ships. Another point of contention to argue the Kapitan Laut's campaigns at sea as merciless was Buisan's captives. While Maguindanao did sell some of them as slaves, they also made it a habit to actually keep others to serve as retainers and fighters to improve the sultanate. Note also how some datus still entered into an alliance with him despite his raids. They recognized not only his strength, but also his sincerity in offering an alternative to colonization, their liberation. As for the captured Spanish, they were usually freed, especially as effect of the agreements they entered with the colonial government in Manila. Overshadowed by the memory of his son Kudarat, Buisan appeared to be a footnote in history. As to his legacy as an admiral of Philippine seas, whether or not he can be regarded as a naval hero or a savage pirate, it remains to be seen by Filipino society.