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Sulu Series · Episode 3 — The Fort That Could Not Be Held: Spain, Combes, and the 1663 Reversal

Spanish-Moro conflict (1578–1663) Sulu Sea, Visayas, Zamboanga

Sulu Series — Episode 3 of 5. ← Previous: Episode 2: The Founding That Cannot Be Proven · Next → Episode 4: The Sulu Zone. Full arc: 1 · 2 · 3 · 4 · 5.

A War That Was Not a War

In the Spanish colonial archive, the 85 years between the first significant Spanish encounter with the Sulu Sultanate in 1578 and the abandonment of Zamboanga in 1663 are documented as a series of military campaigns. The Spanish framework calls them the Moro Wars, treats them as part of the broader project of pacifying a colonial periphery, and records them in the language of Iberian Reconquista — Christian arms against Muslim resistance, with the implicit conclusion that the Christian arms must eventually prevail.

In the actual record of events, almost nothing in that framework is correct.

What occurred in those 85 years was not a colonial war of conquest but a war of mutual frustration between two sovereign powers, neither of which could decisively defeat the other. Spain held Manila and the central Visayas. The Sultanate held the Sulu archipelago, Mindanao’s western and southern coasts, and effective control of the southern sea lanes. Each conducted offensive operations against the other across a contested maritime frontier. Each suffered serious losses. Neither ever achieved the kind of decisive military victory that would have allowed political subjugation of the other.

In 1638, Spain mounted its largest expedition of the period, captured Jolo, built a fort there, and declared the Sultanate conquered. Within a few years, the fort was untenable; within two decades, it was abandoned. In 1663, Spain evacuated Zamboanga itself — its principal southern base — to redeploy forces against more pressing threats elsewhere in Asia. The Sultanate inherited the field. It would not be seriously challenged again for 188 years.

To understand how this happened — and how the Spanish archive came to record it as a war of pacification when it was actually a draw in which Spain blinked first — we have to read the central source carefully.

Combes the Jesuit

The indispensable source for the 1637–1663 phase of the Spanish-Sulu conflict is Francisco Combes, S.J. (c. 1620–1665), a Jesuit missionary stationed in the southern Philippines during precisely the period of the major military operations. His Historia de Mindanao y Jolo was completed shortly before his death and printed in Madrid in 1667. The standard modern edition is the Pastells-Retana critical edition of 1897, which provides scholarly apparatus and corrects errors in earlier printings.

Combes is the single most detailed contemporary source for the Spanish military campaigns against Sulu. He had direct access to expedition commanders, soldiers, and missionary colleagues who participated in operations. He was present in the southern Philippines during the events he describes. His accounts of force sizes, dates, sequences of engagement, and tactical particulars are generally reliable and have been corroborated where independent records exist.

He is also a Jesuit polemicist writing in the Iberian Reconquista tradition, and any honest use of his work has to confront this directly.

Source-criticism card: Combes, Historia de Mindanao y Jolo (1667)

Custody chain: Composed in Manila in the 1660s. Printed in Madrid 1667. Republished with critical apparatus by Pablo Pastells and Wenceslao E. Retana, Madrid, 1897.

Tier: A — primary source, contemporary with events, by an author with direct access to participants.

Reliability — military and operational detail: HIGH. Force sizes, dates, sequences of engagement, casualty figures, fort construction details all corroborate where independent records exist.

Reliability — political analysis: MEDIUM. Combes presents Spanish diplomatic claims as straightforward facts and characterizes Moro political motivations through a Christian-versus-Muslim frame that systematically distorts indigenous political reasoning.

Reliability — religious-cultural characterization: LOW. The Jesuit Reconquista frame casts Moros as enemies of Christianity rather than as a sovereign polity defending its territory; this is ideological rather than analytical.

Use guidance: Cite for events and tactical detail. Annotate explicitly for ideological framing. Never quote Combes on Moro motivations without contextualizing the framing.

The cleanest way to use Combes is to extract his account of what happened and to be skeptical of his account of why. The “what” — the chronicle of fleets, fortifications, sieges, sallies, and losses — is the most detailed surviving record of the period and is largely trustworthy. The “why” — the moral framing, the religious characterization, the implicit teleology of Christian victory — must be read as the work of a Jesuit polemicist rather than as historical analysis.

First Contact: 1578

The first major Spanish military engagement with the Sulu Sultanate came in 1578, just thirteen years after the Legazpi expedition had established Spanish authority in Cebu and Manila. Captain Esteban Rodríguez de Figueroa led an expedition to Jolo with the explicit objective of asserting Spanish sovereignty over the Sulu archipelago and converting its inhabitants to Christianity.

The expedition encountered a polity unlike anything the Spanish had subjugated in the central Philippines. The Visayan and Tagalog datuships of the central archipelago had been organized as small chieftaincies, often in active rivalry with one another, lacking any unified political-religious framework that could mobilize sustained collective resistance. The Sulu Sultanate was structurally different. It possessed a unitary religious-political authority, a hereditary court, a developed administrative system, and most importantly, an ideological framework — Islamic political theology — that could organize and sustain resistance over generations.

Figueroa’s expedition succeeded militarily in the immediate sense: Spanish forces inflicted damage on the Sulu capital and extracted a nominal acknowledgment of Spanish suzerainty. But the political effects were nil. The Sultan continued to exercise authority. The Sulu population continued to identify as Muslim. The Sultanate continued to conduct independent foreign relations with Brunei and other Malay polities.

This pattern — Spanish military success producing no political subordination — would repeat for the next 85 years.

The Long Stalemate (1578–1635)

Between Figueroa’s 1578 expedition and the major Spanish offensive of 1635–1638, the Spanish-Sulu conflict settled into a pattern of mutual coastal warfare. Sulu fleets, sometimes joined by Maguindanao and Iranun forces, conducted seasonal raids against the central Visayas — taking captives, livestock, and stored goods, and disrupting the agricultural base on which the Spanish colonial economy depended for tribute. Spanish forces conducted occasional punitive expeditions against Sulu and Maguindanao, with mixed and rarely durable results.

The governing dynamic was a tactical asymmetry that would prove decisive throughout the period.

Spanish naval power was built around the galley and, increasingly, the heavier galleon. These were vessels designed for European naval warfare in deep water against comparable European vessels. They carried significant artillery — bronze cannon of considerable weight and range. They were powerful in open-water engagements where they could use that artillery to maximum effect.

Sulu naval power was built around the caracoa (also rendered karakoa or kora-kora): a large outrigger war proa, rowed by 50 to 100 oarsmen, with a fighting platform amidships and a lateen sail for use in favorable winds. The caracoa was substantially smaller than the Spanish galley and carried no comparable artillery. But it had two decisive advantages.

First, shallow draft. The caracoa could navigate reefs, bars, and shoal waters that the Spanish galleys could not reach. It could enter river mouths, shelter in mangroves, and approach beaches that no European warship could approach. The geography of the Sulu Sea and the Visayan island chains favored the caracoa absolutely.

Second, speed. With large oar-crews and a light hull, the caracoa was the fastest sustained naval platform in the southern Philippine waters. It could outrun a Spanish galley in any chase, choose the moment of engagement, and disengage at will if a battle went badly.

The combined effect was that Spanish forces could win any open-water artillery duel — but Sulu forces consistently refused to fight on those terms. They engaged when terms favored them; they dispersed when terms did not. The Spanish artillery advantage, which would have been decisive in a European context, was nullified by an opponent who simply would not stand still to be shot at.

This is why Spanish punitive expeditions kept reporting victories that produced no permanent political result. The expeditions could find a Sulu base, attack it, and burn it. They could not pin down the Sulu fleet or destroy its capacity to regenerate. The caracoa fleets dispersed to the deep islands, refit, and returned the following monsoon season.

The 1635–1638 Offensive

In 1635, Spain established its first permanent fortified position in the southern Philippines: the Real Fuerza de Nuestra Señora del Pilar de Zaragoza, at Zamboanga, on the western tip of Mindanao. Fort Pilar, as it has been known since, was strategically positioned to interdict raiding fleets passing between the Sulu Sea and the Visayan waters.

Construction of Fort Pilar marks the beginning of Spain’s most sustained attempt at military pacification of the southern Philippines in the 17th century. With a fortified base from which to operate, Spanish forces could conduct longer-range and more systematic operations than had been possible from Manila. The strategy reached its high point in 1638 with a major expedition against Jolo itself.

The 1638 expedition was commanded by Governor-General Sebastián Hurtado de Corcuera. It assembled a force of approximately 80 vessels and over 2,000 soldiers — by far the largest Spanish military effort against Sulu to that date. The expedition reached Jolo in January 1638. Combes provides extensive detail on the assault.

Spanish forces successfully landed and assaulted the Sulu capital. The Sultan and his court withdrew to the interior of the island. After a period of siege, Spanish forces took the Sultanate’s principal fortified position at Lapuk and constructed a Spanish fort on the site. Corcuera declared the conquest complete and returned to Manila in triumph. Te Deums were sung. Dispatches were written. Madrid was informed that Sulu had been added to the Spanish dominions.

It was, militarily and politically, almost entirely unreal.

The Fort That Could Not Be Held

The Spanish fort at Jolo, garrisoned by a permanent Spanish detachment from 1638, was untenable from almost the moment of its construction. Combes documents the conditions:

  • The garrison was under near-continuous attack or threat of attack by Sulu forces operating from the interior of Jolo island and from neighboring islands
  • Supply by sea was difficult and contested — the Sultan’s allied Iranun forces interdicted Spanish supply convoys whenever monsoon and force balance permitted
  • Disease attrition among the Spanish garrison was catastrophic — Combes records mortality rates that exceeded combat casualties by significant margins
  • Local food procurement was nearly impossible because the surrounding population was uniformly hostile
  • The fort’s strategic purpose — to deny Sulu its capital and to project Spanish authority over the archipelago — was not achieved because the Sultanate simply continued to function from alternative locations

The Spanish authorities in Manila understood the situation accurately. Repeated debates in the Royal Audiencia and in the colonial administration considered abandoning the Jolo position. The fort was maintained, with declining vigor, through the 1640s and into the 1650s, but it never functioned as a base for the pacification of Sulu. It was a strategic embarrassment maintained for reasons of imperial prestige rather than military utility.

The Sultanate, meanwhile, continued to operate. The Sultan continued to receive foreign envoys. Sulu fleets continued to raid the Visayas. Trade with China continued through the entrepôts of the southern archipelago. The “conquest” announced in 1638 had altered nothing structural about Sulu sovereignty.

It is worth pausing on a vocabulary problem that the Spanish archive embeds in the historical record. Throughout the period 1578–1663, Spanish documents consistently characterize Sulu and allied raiding activities as piratería — piracy. The term is not neutral.

Under the European law of nations as understood in the 17th century, “piracy” had a specific legal meaning. A pirate was a person who attacked shipping and coastal targets without the authority of any sovereign — a stateless predator, the legal enemy of all humanity (hostis humani generis), subject to summary execution wherever caught. This legal category was distinct from inter-state warfare, in which combatants on both sides held protected status as agents of recognized sovereigns.

The Sulu raiding fleets were not pirates in this legal sense. They were the naval forces of a recognized sovereign polity — the Sultanate — conducting offensive operations against another sovereign — the Spanish Crown’s Philippine territories. By the legal standards of the period, the correct characterization was either inter-polity warfare or, at most, authorized privateering (the issuance of letters of marque by a sovereign to private raiders).

Spain’s persistent characterization of Sulu raids as “piracy” served two functions. It denied the Sultanate the dignity of sovereign status, framing it as a non-state nuisance rather than as a peer political actor. And it justified Spanish responses outside the constraints of inter-state war — summary execution of captured Sulu combatants, refusal to negotiate prisoner exchanges, denial of diplomatic recognition.

This legal-rhetorical move would persist into the American colonial period (1899–1946) and beyond, shaping Western and even Filipino characterizations of Sulu and Bangsamoro political action well into the 20th century. It is a small but important case of how colonial legal vocabulary can durably distort historical understanding.

The “Moro” Word

The same period saw the consolidation of another distorting vocabulary: the word Moro itself.

The term was a direct semantic transfer from the Iberian Reconquista. Spanish colonizers brought to the Philippines the religious-enemy framework that had organized eight centuries of conflict against Muslim polities in Iberia and North Africa. Moor — Moro in Spanish — was the term Iberians had used for those Muslim adversaries. When Spanish forces in the Philippines encountered Muslim populations in Mindanao and Sulu, they naturally applied the same term. David P. Barrows, writing in 1905, made this transfer explicit:

“Those who came from Morocco had been always known as ‘Moros,’ and this name was naturally given to those Mohammedans whom the Spaniards found in the Philippines.”

The semantic transfer carried with it the entire ideological apparatus of the Reconquista — the framing of religious enmity, the assumption of legitimate Christian conquest, the rhetorical denial of legitimate Muslim political authority. The Spanish-Sulu conflict was filtered through this apparatus and recorded in its terms. Combes writes within it. So do nearly all Spanish-period sources.

It is also worth noting what the Reconquista framework concealed. The Sulu peoples were not, in fact, foreigners or recent arrivals. They were indigenous to the southern archipelago. Tausug, Sama, Yakan, Iranun, and Maguindanao communities had inhabited their territories for centuries before Spanish contact. The Spanish framing presented them as something like a Muslim invader-presence to be expelled — an imaginative inversion of the actual fact, which was that the Spanish were the recent arrivals attempting to subjugate indigenous peoples whose claim to the territory long predated any European presence.

The word “Moro” carried this inversion, and it carried it for centuries. The reclamation of the term as a positive self-designation by the Moro National Liberation Front in 1969 — covered in Story 5 of this series — is a late-20th-century reversal of a 16th-century imposition. The reversal would not have been necessary if the imposition had not been so durable.

The 1663 Evacuation

The structural turning point of the period came not in Sulu but in the wider geopolitical context of the 17th-century Pacific. By the early 1660s, Spain faced two acute threats to its position in Asia.

The first was the Dutch East India Company (VOC), which had been steadily expanding its naval and commercial position in maritime Southeast Asia and which posed an ongoing threat to Spanish trade and territory.

The second, and more immediately alarming, was the rise of Koxinga (Zheng Chenggong), the Ming-loyalist warlord who had expelled the Dutch from Taiwan in 1662 and was reported to be planning an invasion of the Spanish Philippines. The threat was credible. Koxinga commanded substantial naval forces. Manila was vulnerable. Spanish authorities concluded that the southern garrisons — Zamboanga and the Maluku island fortifications — had to be evacuated to consolidate forces for the defense of Luzon.

In 1663, the order was given. The Spanish garrison at Zamboanga was withdrawn. Fort Pilar was abandoned. Spanish forces in Maluku were evacuated. The southern frontier of Spanish Philippine power retreated, in a single year, by hundreds of nautical miles.

The Koxinga invasion never materialized — Koxinga died in 1662, and his successor’s attention turned elsewhere. But the evacuation, once executed, was not reversed. Zamboanga would not be re-occupied by Spain for another 55 years, and Jolo would not be re-occupied for another 188 years. The Sulu Sultanate, which had been under sustained Spanish military pressure for nearly a century, suddenly found itself at its greatest reach of effective independence. Story 4 in this series picks up the Sultanate’s life in this newly opened space.

The Two Sovereignties, Revisited

The pattern that becomes explicit in 1915 — the distinction between the legal-formal sovereignty of the Sultanate and the lived sovereignty of the Sulu peoples — is already operating in the period of the Spanish-Moro Wars. It is worth naming, because it changes how we read the Spanish “victories” of the 17th century.

Throughout the 1578–1663 period, Spain repeatedly attacked the Sultanate as a political-military entity. It assaulted the Sultan’s capital, captured his fortifications, and at times forced him into peace agreements that included nominal acknowledgment of Spanish suzerainty. These actions targeted the legal-formal sovereignty of the Sultanate at its apex — the institution of the Sultan, the court, the centralized military command.

What Spain did not do, and could not do, was reach the lived sovereignty of the Sulu peoples beneath the Sultanate. The Tausug villagers continued to live as Tausug. The Sama-Bajau communities continued to fish, dive, and move along their accustomed sea routes. The Yakan farmers continued to cultivate their land. The communities continued to govern themselves through their datus, their kin-group authorities, their customary law, their religious life. None of this was touched by even the most successful Spanish punitive expedition.

This is why the “Sultanate has been conquered” reports that flowed back to Madrid after 1638 were structurally misleading. Spain had taken the Sultan’s principal fort and announced his subjugation — but the people who made the Sultanate possible, who provided its soldiers and sailors and farmers and traders, were beyond Spanish reach. When the Spanish garrison weakened, the Sultanate reconstituted itself from the still-intact substrate of the population. There was nothing for the Spanish to conquer because the actual sovereignty they would have needed to extinguish was distributed across thousands of households, kin-groups, and communities — each of which would have needed to be individually subdued, and none of which could be reached by an artillery fort on a coast.

This is a recurring lesson of the colonial period in maritime Southeast Asia. European powers consistently attacked the apex institutions of indigenous polities and consistently mistook the apex for the whole. When the apex was struck, the structure beneath continued to operate, and when European pressure relented, the apex reconstituted. The Spanish encounter with Sulu in the 17th century is a paradigm case.

The Stage That 1663 Set

What the 85 years of Spanish-Sulu conflict left behind, in the end, was a paradox. Spain had committed enormous resources to subduing Sulu and had achieved nothing durable. Sulu had survived sustained military assault and had emerged, in 1663, freer than at any point in the previous century. The Sultanate’s legal-formal sovereignty was intact. The lived sovereignty of its peoples was, if anything, strengthened by the experience of resistance.

But something else had also been built in those 85 years, on both sides, that would shape what came next. Spain had constructed Fort Pilar at Zamboanga — a fortification that, although abandoned in 1663, would be re-occupied in 1718 and would become the long-term anchor of returning Spanish presence. The Sultanate had developed its military and naval capacity, refined its alliances with the Iranun and other communities, and consolidated the long-distance trading networks that would feed the Sulu Zone economy of the next century. Both sides had inherited from the conflict the capacity to fight again, more effectively, when the geopolitical balance shifted.

The 1663 evacuation was not the end of Spanish-Sulu relations. It was an intermission. What it did was give Sulu the time and the unobserved space to develop into the maritime power that the next story in this series describes — the Sulu Zone of the 18th and early 19th centuries, the largest non-European maritime sovereignty of its region. The Sultanate’s two centuries of effective independence began at the moment Spain walked away from Zamboanga.

The fort that could not be held was, in the end, not a Spanish failure of will. It was a structural impossibility. There was no available means by which Spain, with the technology and force projection of the 17th century, could subjugate a maritime polity whose sovereignty was distributed across an archipelago and whose military advantage lay in shallow water and seasonal mobility. Spain learned this in 85 years of trying. The lesson would not have to be re-learned for nearly two centuries — and when it was re-learned, in the 1840s and after, it would be in the changed context of steam power, industrial artillery, and modern colonial techniques. The 17th-century stalemate would be undone not by better Spanish strategy but by a transformation of the technological basis of warfare itself.

That transformation, and the dismantling it made possible, is the subject of the final story in this series.

Quarantined Claims

Applying the framework laid out in Story 1, the following claims are explicitly excluded:

  • QUARANTINED: That the 1638 Spanish capture of Jolo constituted “the conquest of Sulu.” Spain took the Sultan’s principal fort and announced subjugation in dispatches; the actual political effect on Sulu sovereignty was nil. The Sultanate continued to function and to conduct independent foreign relations throughout the period of the Spanish fort.
  • QUARANTINED: That Sulu raiding constituted “piracy” in any legal sense. Under the European law of nations as understood in the 17th century, piracy required statelessness. Sulu fleets operated under the authority of a recognized sovereign and conducted inter-polity warfare. “Piracy” was a Spanish legal-rhetorical move, not a neutral description.
  • QUARANTINED: That “Moro” is a neutral ethnographic term. It is a direct semantic transfer from the Iberian Reconquista, carrying religious-enemy connotations; its 20th-century positive reclamation by Bangsamoro movements is a reversal of a 16th-century imposition, not a continuity.
  • QUARANTINED: That the 1663 evacuation of Zamboanga represented a Spanish strategic choice from a position of strength. It was a forced retreat driven by the Koxinga threat and the Dutch competition; Spain abandoned a position it could not effectively hold and that had failed to produce the political results sought.
  • QUARANTINED: That Combes’s characterization of Moro motivations is reliable historical analysis. His operational and tactical detail is generally trustworthy; his account of why his Moro adversaries acted as they did is filtered through a Jesuit Reconquista frame that systematically distorts indigenous political reasoning.
  • QUARANTINED: That the Spanish-Sulu conflict was a conventional colonial war ending in eventual Spanish victory. It was a war of mutual frustration between two sovereign powers; Spain blinked first in 1663 and would not return in force for nearly two centuries. The 19th-century steam-and-artillery dismantling is a separate event with separate causes.

Primary sources: Francisco Combes, S.J., Historia de Mindanao y Jolo (1667), critical edition by Pablo Pastells and Wenceslao E. Retana (Madrid, 1897); Blair & Robertson, The Philippine Islands, 1493–1898, vols. XXIV–XXVI (covering the 1620s–1660s) and selected earlier volumes for the 1578 expedition; Antonio de Morga, Sucesos de las Islas Filipinas (1609); contemporary Audiencia and royal correspondence on Mindanao operations. Secondary: Cesar Adib Majul, Muslims in the Philippines (1973), especially chapters on the 17th-century conflict; Najeeb M. Saleeby, The History of Sulu (1908); Reynaldo Ileto, Magindanao 1860–1888: The Career of Datu Utto of Buayan (1971); William Henry Scott, Slavery in the Spanish Philippines (1991); Peter Gowing, Muslim Filipinos: Heritage and Horizon (1979); David P. Barrows, A History of the Philippines (1905) — cited specifically for the documentation of the “Moro” semantic transfer; Linda Newson, Conquest and Pestilence in the Early Spanish Philippines (2009) for the demographic and disease context; Anthony Reid, Southeast Asia in the Age of Commerce, 1450–1680, vol. 2 (1993). Internal cross-references: see “The Three Kings of Sulu” for the pre-Sultanate evidentiary base, “The Sulu Zone” for the Sultanate’s life in the period that opened with the 1663 evacuation, and “The Karakoa” for the broader maritime tradition of which the Sulu caracoa was part.