Spanish occupation of Jolo (1638)

On January 4, 1638, the Spaniards landed on the beach near Jolo and staged their first assault on the fortress, with Corcuera himself leading the troops.[2] Though the force came with much fury and with better arms compared to those in the fort, the attacks were repulsed. Bombardment of the fort continued for weeks after the initial assault, with the Sulus obstinate and holed up within the fort, while the Spanish-Filipino force regrouped on their ships. Another attack was led by Corcuera and the Sulus remained resistant. With either side gaining any ground, and the current siege situation favoring the Sultan, who had a steady supply of food from the interior of the island, a period of stalemate ensued.

After nearly 3 months of stalemate in Jolo, with neither side gaining or losing ground, and both sides suffering mounting casualties, it looked as though the Sulus had once again repelled the assault on their capital. But soon, a mysterious disease, described as a "tropical disease" [1] (presumed to be malaria) entered the fort and ravaged its defenders. Many Sulus died from the sudden epidemic, and eventually, Sultan Wasit called for a retreat, abandoning the fort and the town and sailing to Dungun, Tawi-Tawi in the southernmost reach of the Sultanate. The Spaniards later occupied the town and fought off the remaining resistance in the fort, establishing a garrison within the town and reconstructing its Kutas and fortifications.

After the initial triumph of the Spaniards in Jolo, Sultan Wasit was faced with a humiliating defeat at the hands of de Corcuera. Initial assaults on the town of Jolo were conducted by the Sulu Datus who were left behind, under the command of Wasit himself. However, no major assault occurred until presumably 1640. Regrouping and calling for reinforcements from Tawi-Tawi, he organized a counter-offensive [1] to drive the Spaniards out of his domains.

However, he was not to directly lead this assault. The Datus of Sulu were now to be led by the Sultan's son, Pangiran Salikula. It was around this time that Salikula was named de facto Sultan of Sulu, due to his father's old age. It would take another 5 years of conflict before the Spaniards would agree to a treaty, and finally leave Jolo.

The bulk of Wasit's army now consisted of the forces of his Datus, and the Datus of Tawi-Tawi, his Bornean and Makassarian allies either killed or captured. The fate of Jolo rested on the armies of the Datus and Sultan's army. The initial counterattack ended up pushing the front line to the mountain of Bud Datu, overlooking the then Spanish town of Jolo. for many months, the Datus of Sulu began fighting a bloody war in the jungles at the foot of the mountain, it became another stalemate for a while.

Soon, the battle began favoring the Sulus, as the garrison of the Spaniards was continually depleted, and Corcuera was absent at this time, attending to duties in Manila. Wasit was also no longer leading the Datus in battle, he was considered old and his son was entrusted with the command on the assault.[1]

It is unclear how long this battle lasted, or how severe the casualties on either sides were, what is widely believed, however, is that Sultan Wasit ordered that the Mountain overlooking Jolo, was to be named "Bud Datu" meaning "Mountain of the Datu" to commemorate the sacrifice of the Datus of Sulu in their long fight with the Spaniards.[1] The Datus of Sulu hunkered down and built their Kutas on the Mountain's slopes, in order to consolidate their minor gains.

On March 25, 1644, Wasit dispatched his Son, Pangiran Salikula, along with a Dutch fleet from Batavia to bombard the remaining Spaniards in the Jolo garrison.[1] No decisive land battle occurred during this period, and the Dutch presumably had no further involvement with the Sulu Sultan afterwards. A period of relative peace once again ensued in Jolo, as the garrison was now cut off from reinforcements and virtually surrounded.

Some time in 1645, the combined forces of Pangiran Salikula, the acting Sultan of Sulu and a certain Sultan Nasir ud-Din, who many believe to be Sultan Kudarat, led a final assault on the garrison, killing and capturing the remaining Spanish forces there and finally occupying Jolo.

It is unclear what occurred between the Sulu reconquest of Jolo and the final treaty signed with Manila and Sulu. It is believed, however, that due to an earlier marriage agreement with Qudarat, or Nasir ud-Din, his presumed name in Sulu,[3] Salikula would not continue to rule as de facto Sultan, or even reign as full Sultan in fact. Rather, Wasit is believed to have given the throne of Sulu to Nasir ud-Din as a gesture of gratitude and of obligation, as Nasir ud-Din was his son-in-law, due to an earlier marriage agreement between Sultan Wasit's daughter and Sultan Qudarat.

Sultan Qudarat was officially crowned Sulu Sultan Nasir ud-Din in Bauang or Jolo, sometime in late 1645, while Salikula and Wasit remained in Tawi-Tawi. On April 14, 1646, The Manila Spanish government signed a peace treaty with Sulu Sulta Nasir ud-Din recognizing the Sultanate's continuing independence from Spain, his sovereign rights to extend up to the Tawi-Tawi Group as far as Tup-Tup and Balabac islands in Palawan, and his monopoly on Maguindanao-Sulu-Borneo trade.[1][5]

Sultan Nasir ud-Din ruled until 1648, when, after the death of Wasit's son, Salikula (sometimes spelled Sarikula) Wasit asserted his right to rule as Sultan once more, and Nasir ud-Din was asked to step down from the throne. However, Sultan Muwallil Wasit's second reign would be short lived, as he died around 1649 or 1650, giving way to his son, Pangiran Bakhtiar to become Sultan.