Portugal in the Persian Gulf: Maritime Power and Strategic Continuity

The current geopolitical environment in the Persian or Arabian Gulf,[1] marked by heightened tensions involving the Islamic Republic of Iran, the United States of America and the State of Israel, has once again placed the Strait of Hormuz at the centre of the global strategic architecture. Due to its geographic configuration and systemic function, the Strait constitutes one of the most critical maritime chokepoints in global trade, through which passes over 20% of global energy flows. Instability in Hormuz therefore generates immediate systemic effects, as reflected in recent fluctuations in international energy and financial markets.

On 7 April, a two-week cessation of hostilities was reportedly agreed between the parties involved, with subsequent discussions towards a broader settlement initiated on 11 April in Islamabad under the mediation of the Prime Minister of Pakistan, Shehbaz Sharif. These developments were almost immediately interrupted 24 hours later and remain fragile and subject to significant reversals.

Within this context, the possibility of Iran seeking to control, condition, or levy charges on maritime passage through Hormuz, effectively transforming it into a form of strategic toll mechanism, raises fundamental concerns regarding freedom of navigation in international straits under the United Nations Convention on the Law of the Sea (UNCLOS), regional stability, and the functioning of the global economy.[2]

The military escalation, widely assessed as having been shaped through Israeli operational initiative, appears to have contributed to increased United States strategic involvement, with elevated risks and significant humanitarian, political, and economic consequences. Regionally, this has affected relations among Gulf states and complicated existing channels of engagement with Iran.

From an economic perspective, Qatar is among the most exposed actors, not only due to geographic proximity but also because it shares with Iran the world’s largest natural gas field (North Dome / South Pars). This cross-border geological continuity reflects a structural interdependence that coexists with long-standing political and strategic divergence.

The contemporary centrality of Hormuz is not without historical precedent. During the Sixteenth century, Portugal developed a maritime system explicitly based on the control of strategic chokepoints rather than extensive territorial occupation.[3] Control of Hormuz, when integrated with Goa and Malacca, enabled the construction of a global maritime architecture based on the regulation of commercial flows. This historical experience provides an analytical framework for understanding the persistence of the Gulf’s strategic relevance.

Portguese strategic fortress establishments and the Tordesillas treaty lines established in 1494.

The Portuguese maritime expansion must be understood within the structural transformations of the Fifteenth century. The fall of Constantinople in 1453 and the subsequent Ottoman dominance over key Eurasian trade routes significantly constrained European access to spices and Eastern commodities.[4] In response, the Portuguese Crown, under King John II and later King Manuel I, developed a long-range maritime strategy based on the progressive exploration of the African coastline and the search for a direct sea route to India. Vasco da Gama’s voyage of 1498 marked the operational realisation of this strategy and the beginning of a new global maritime system.

However, access to the Indian Ocean did not in itself guarantee control over established commercial networks. The Indian Ocean was already a highly structured maritime space, dominated by interconnected trading systems involving Ottoman, Arab, Persian and Indian actors.[5] Portuguese entry therefore required the construction of a coercive and regulatory maritime framework. Unlike contemporary continental empires, Portugal developed an expansion model based on selective occupation of strategic maritime nodes.

The Portuguese fortress of Muscat in Oman

This approach may be understood as a form of nodal geostrategy, prioritising key locations capable of influencing large-scale maritime flows.

The three principal nodes in this system were:

Hormuz, controlling access to the Gulf and functioning as the system’s ‘strategic brain’, supported by ‘eyes’ in surveillance structures in Bahrain (Qal’at al-Bahrain, also known as the Bahrain Fort or Portuguese Fort) and at Al Ruwaida on the northern coast of Qatar,[6] as well as a series of fortifications in Oman, particularly in the defence of the capital, Muscat, acting as the system’s ‘muscles’, including the forts of Al Jalali (formerly São João), Al Mirani (formerly São Tiago), Al Muttrah, and Al Ayjah in the coastal town of Sur.

Goa, as the ‘administrative heart’ of the Estado da Índia, functioned as the political, fiscal, and military command centre of the imperial system in the Indian Ocean. The city coordinated the governance of Portuguese possessions along the western coast of India, ensuring the logistical organisation of naval forces, the administration of revenues derived from Asian trade, and the projection of power over key coastal enclaves, thereby performing a systemic integrative function across the various operational theatres of the Asian empire.

Malacca, dominating the connection between the Indian Ocean and the South China Sea, constituted the ‘strategic throat’ of the Asian commercial system, controlling maritime flows between the Indian Ocean and the Sino-maritime sphere. Its position enabled the interception and taxation of spice routes originating from the islands of Southeast Asia, functioning as a point of convergence and filtration for inter-regional trade, essential to the global architecture of the Estado da Índia.[7]

The effectiveness of this strategy lay in its economic and military rationality. Rather than dispersing resources across an extensive geo-maritime occupation, Portugal concentrated them in locations of high strategic value, thereby exercising asymmetric control relative to its available means over vast and commercially significant maritime spaces. This model operated as an integrated system, in which the loss of any single node would compromise overall effectiveness.

Although Hormuz fell in 1622, its conquest 107 years earlier, in 1515 (following a failed first attempt by Afonso de Albuquerque in 1507), constituted a decisive milestone in the consolidation of Portuguese presence in the Persian Gulf. It was fundamental to Portuguese maritime predominance in the Indian Ocean, broadly situated between the early Sixteenth century and the first quarter of the Seventeenth century – a period during which Lisbon succeeded in controlling the principal maritime chokepoints. This form of dominance, while never territorially absolute, was based on a network-control logic and persisted in contested form until approximately 1650.

Afonso de Albuquerque was not merely a military commander, but a strategic thinker with a comprehensive vision of Portugal’s role in the world. Beyond commercial control, he advocated a policy of structural transformation of the region, including its Christianisation and integration into a political order aligned with Portuguese interests. This vision implied not only the consolidation of deeper forms of control, but also the integration of local elites and the diffusion of Christianity as an instrument of cohesion and legitimacy.[8]

However, this strategy encountered limitations in the political orientation of King Manuel I, who favoured a more pragmatic and commercially driven approach, particularly in a context in which the Indian Ocean was already characterised by intense competition and multiple threats to Portuguese interests.

The analysis of Portuguese expansion in the Persian Gulf raises a pertinent question: to what extent did high-level political decisions condition the scope of imperial strategy?

It is plausible to suggest that, under the reign of King John II, Albuquerque’s vision might have found stronger institutional support. John II demonstrated an exceptional capacity for strategic conception and a firm determination in the execution of political objectives. Had Albuquerque operated under his authority, it is conceivable that he would have been authorised to pursue a more ambitious programme of regional domination and transformation. Such a scenario might have led to a profound reconfiguration of the political, social, and religious geography of the Persian Gulf. While speculative, this hypothesis underscores the importance of strategic decision-making in shaping historical outcomes.

From the late-Sixteenth century onwards, the Portuguese system began to face increasing challenges. The Ottoman Empire, the Safavid state, and subsequently emerging European powers such as England and the Netherlands, progressively contested Portuguese dominance in the Indian Ocean. The loss of Hormuz in 1622, resulting from an alliance between Persian and English forces, marked a decisive turning point. The removal of this key node significantly weakened the coherence of the Portuguese maritime system, although residual presence persisted for several decades.

The Portuguese experience in the Persian Gulf constitutes a notable example of applied strategic foresight. By prioritising the control of maritime chokepoints over extensive sea areas and territorial occupation, Portugal anticipated key principles of modern maritime geopolitics.

It is therefore important to emphasise this example of strategic-operational thinking, leadership, and vision demonstrated by the Portuguese during their extensive maritime expansion, combining understanding, cooperation, and inclusion within a context of considerable political, cultural, and geographical complexities. The ability to conceive and implement a global system of maritime control, based on the articulation of strategic nodes and the intelligent management of limited resources, represents an achievement of exceptional historical significance and one of Portugal’s most enduring contributions to global history.

This model, grounded not solely in force but also in negotiation, adaptation, and the integration of diverse local realities, reveals a level of strategic sophistication that transcends the purely military dimension, reflecting a comprehensive and innovative approach to power projection.

The Portuguese legacy should therefore serve to inspire and motivate younger generations, not only in Portugal but elsewhere, fostering a culture of strategic and critical thinking, global ambition, and a strong capacity for adaptation in a world of constant transformation, where challenges increasingly demand vision, resilience, and foresight. It may also, perhaps, serve as a reference and source of learning for those who seek to exercise influence or authority over others.

References

[1] The historical and internationally recognized name by the UN is Persian Gulf. However, for political and national identity reasons, the Arab countries of the region frequently use the term Arabian Gulf. The dispute over the name reflects geopolitical tensions between Iran (ancient Persia) and the Arab nations. It should be noted that, for general knowledge, Persian Gulf is the historical name, used since Roman times (sinus persicos) and adopted by most maps and international institutions, while Arabian Gulf is the term adopted by the nations of the Gulf Cooperation Council (GCC), which includes the Kingdoms of Saudi Arabia and Bahrain, the United Arab Emirates, the States of Qatar and Kuwait, and the Sultanate of Oman.

[2] United Nations Convention on the Law of the Sea (UNCLOS 1982), Articles 34-45 (International Straits).

[3] Sanjay Subrahmanyam, The Portuguese Empire in Asia 1500–1700 (London: Longman, 1993).

[4] A. R. Disney, A History of Portugal and the Portuguese Empire (Cambridge: Cambridge University Press, 2009).

[5] M. N. Pearson, The Indian Ocean  (London: Routledge, 2003).

[6] A small settlement where an archaeological site reveals clear indications of Portuguese presence. This was not a “Portuguese fort built from scratch,” but rather a location integrated into the Portuguese operational theatre in the Persian Gulf. At Al Ruwaida and nearby sites in northern Qatar, what can be observed are coastal defensive structures with simple rectangular or quadrangular layouts, constructed from limestone and coral stone, along with low-height watchtowers, features consistent with defensive patterns employed in the Gulf during the Portuguese period and reflecting a local adaptation of Iberian coastal fortification techniques. Accordingly, in the case of Al Ruwaida, Portuguese presence is not expressed through unequivocal fortified structures of Iberian construction, but rather through an indirect integration into the Portuguese coastal surveillance system in the Persian Gulf.

[7] C. R. Boxer, The Portuguese Seaborne Empire 1415 – 1825  (London: Hutchinson, 1969).

[8] T. F. Earle and J. Villiers (eds.), Afonso de Albuquerque: Caesar of the East (Warminster, 1990).