By the start of the 20th century, Portugal’s military capacities were primarily engaged with “pacification” campaigns in its remaining African and Asian colonies. The gulf in quality that separated its armed forces from those of wealthier European states was vast and growing – nonetheless, the Portuguese government adopted an interventionist position, working hard to earn a place in the coalition fighting Germany. Though a Portuguese Expeditionary Corps (Corpo Expedicionário Português, CEP) was present on the Western Front and additional campaigns were fought in Africa, the limited number of men mobilized meant that the experience of combat and its lasting consequences was reserved for a small percentage of the male population. Moreover, Portugal’s participation in the war was imposed on an uncomprehending population, by no means enthusiastic about the conflict, and on a sceptical senior ally, in the form of the British army. This article will provide a brief overview of the country’s military contribution and the constraints its leaders faced.

The War at Sea

The Portuguese navy was, in 1914, small and outdated, and therefore incapable of facing up directly to a modern enemy. Also missing was the infrastructure needed for significant advancements in naval power.[1] Decades of neglect and under-investment, as well as ongoing political instability, were to blame for this situation. The country’s few warships could not risk a direct confrontation with enemy surface vessels, and were equipped with neither depth charges nor mine-sweeping equipment, being thus powerless against enemy submarines. Over the course of the war, a small number of trawlers were eventually adapted for this purpose, but in general the navy’s contribution to the struggle against Germany was small. The high public profile of Admiral Jaime Leote do Rego (1867-1923), the naval division’s commander, could not disguise the fact that, for their own safety, the navy’s warships had to remain in port most of the time. Given the navy's strong republican and interventionist sentiment, this was a source of embarrassment to the regime. At best the fleet could provide escorts for the merchant vessels ferrying troops and equipment to France, Angola and Mozambique – but even this task proved, at times, beyond its ability, and most shipments of troops to the French port of Brest were in fact escorted by British destroyers. In August 1917, the British withdrew their remaining merchant vessels from the Lisbon-Brest run, essential for the upkeep of the CEP, leaving this task to the Portuguese navy, whose “auxiliary cruisers” – converted merchant ships – were wholly unsuited for the task.

The navy participated in the effort to keep access to the most important of all Portuguese ports, Lisbon and, to a lesser extent, Leixões, open, but was not present to counter the shelling of ports in the islands of Azores and Madeira by German U-boats. It also supported military operations in Mozambique, notably the failed attempt to cross the Rovuma river on 27 May 1916.[2] Its highest profile naval engagement of the war was the one-sided October 1918 fight between an auxiliary patrol vessel (a former trawler), the NRP Augusto de Castilho, and U-139, commanded by submarine ace Lothman von Arnauld de la Perière (1886-1941). The Portuguese captain, José Botelho de Carvalho Araújo (1881-1918), ordered his small and weakly armed vessel to engage the U-boat, thus protecting the escape of the steamer S. Miguel, which it was escorting en route from Funchal, in Madeira, to Ponta Delgada, in the Azores. The fight raged for two hours until, their captain dead and the Augusto de Castilho immobilized, the Portuguese surrendered. The aftermath of the battle was filmed from the U-boat; the images are still available.[3] Also in 1918, after an unsuccessful naval revolt against President Sidónio Pais (1872-1918), a navy battalion was assembled and dispatched to Mozambique to fight on foot, a measure generally understood at the time as a punishment.

The War in the Air

The first steps towards the projection of Portuguese military strength into the air came in 1912. Minister of War General Pereira d’Eça (1852-1917) commissioned studies into which aeroplanes to purchase, as well as how best to establish an “aeronautical school” in Portugal. A decree was issued creating such an institution in May 1914, with work on its infrastructure beginning the following year in Vila Nova da Rainha, after which the first aeroplanes – and instructors – arrived. A first batch of officers was sent to France to learn how to fly at the close of that year, with an additional three being sent to Great Britain in 1915. They and their recently arrived aircraft were on hand for manoeuvres involving the troops destined for the CEP in France in the autumn of 1916. By this time the navy too had begun to show interest in the development of its own air wing.[4]

The CEP was initially designed to have an aerial component, and its intended pilots, led by Lieutenant Óscar Monteiro Torres (1889-1917), received additional training with a Royal Flying Corps squadron operating out of Béthune while others trained with a French squadron. In the end this effort came to naught, as no distinct Portuguese air squadron emerged. Nonetheless, thirteen Portuguese pilots went on to fly combat missions with the French military aviation. Monteiro Torres, for instance, was shot down on 19 November 1917 while flying his Spad 7 fighter. Wounded, he landed his plane behind enemy lines, was captured, and died in a German military hospital.[5]

A small aerial force sent to northern Mozambique in 1917 had practically no impact on military operations there.

The War on Land: Africa

If at sea and in the air the Portuguese contribution to the war against Germany was almost negligible, given the paucity of available means, the situation on land was, in theory, different. Existing stocks of weapons were not obsolete; the provision of advanced material was easier and cheaper to secure; and the training, or reskilling, of the existing forces could also be managed by the ever-expanding Entente war machine, well used to the task of transforming the alliance’s vast reserves of manpower into capable soldiers. However, the task facing the Portuguese army was complicated by both the potential need to fight in very different theatres – the main Portuguese colonies of Angola and Mozambique as well as France itself – and the stop-start diplomatic process that eventually resulted in Portugal’s belligerence. As a result, the first clashes between Portuguese and German forces occurred well before the two countries were officially at war.[6] In the case of the battle of Naulila, in December 1914 (see below), the defeat of the Portuguese led to a major anticolonial revolt that spread across southern Angola, requiring a massive military response to suppress. Mozambique would also see a number of very significant anti-Portuguese revolts during the conflict.[7]

The Portuguese army had a long history of campaigning in Angola and Mozambique and the conditions its forces encountered there should not have come as a surprise. However, colonial “pacification” campaigns had been characterized by technological superiority, a significant reliance on African auxiliaries, and the targeting of the economic infrastructure of those tribes whose submission to Lisbon’s authority was required. Fighting the Germans proved a very different proposition. The expeditions sent to Angola in 1914, operating in recently subdued territory, were immobilized not knowing the intentions of the German forces across the border, which they themselves could not cross. An initial German incursion, in October, led to a number of casualties at the hands of the Portuguese. In retaliation, a series of Portuguese border posts were attacked, their garrisons suffering casualties. Tensions mounted on the border, but the German government proclaimed itself innocent and unable to contact the authorities in South-West Africa, so the peace between Lisbon and Berlin held. On the ground, the Portuguese forces led by Lieutenant-Colonel Alves Roçadas (1865-1926), made up mostly of conscripts – many wholly unsuited for the conditions they would face – were surprised by the aggressiveness, mobility, and firepower of the Germans once these decided to attack in greater numbers.[8] Resolving to deal with the threat to the north once and for all, they launched a carefully planned assault in December, leading to the loss of the fort of Naulila, where the Portuguese garrison made an unsuccessful stand on 18 December.[9] Fortunately for them, the Germans, under pressure from South African forces, withdrew swiftly from Angola. All that remained for the Portuguese to do was to reassert their authority in the south of the colony, a procedure for which traditional – and brutal – tactics sufficed.

The defeat suffered at Naulila should have opened Portuguese eyes to the challenge posed by German forces in Africa, but this was not the case and there was little official reflection on what had gone wrong. The expeditions rushed to Mozambique before and after the German declaration of war, although larger, were no better prepared for the task at hand than their counterparts in Angola. There was a political imperative to invade German territory in order to be seen as contributing to a decisive victory, but the estimates for what the units gathered in northern Mozambique could achieve were overblown. After a symbolic victory – the occupation of the disputed territory known as the “Kionga Triangle”, which was situated at the mouth of the Rovuma river and formed the border between most of Mozambique and German East Africa – the Portuguese attempted, in May, to cross the Rovuma into German territory in a joint army-navy operation. They were, however, beaten back by heavy German fire. Impelled by the political need to attack – as well as the realization that his columns would waste away from disease if he did not – the commander of the main expedition sent out in 1916, General Ferreira Gil (1858-1922), watched impotently as a large Portuguese force was surrounded in November at the captured German fort of Newala. Gil, who had no African experience and was chosen for his republican credentials, was not prepared to face the more mobile and aggressive German forces, whose artillery outranged that of the Portuguese. The invading force had to abandon Newala in the cover of night, its retreat to Mozambique turning into a rout which ended only at the port of Palma, under the protective cover of British naval guns. Never again did the Portuguese cross over into German territory; from that moment on they were on the defensive in East Africa.

Worse was to come in November 1917, when the German forces led by General Paul von Lettow-Vorbeck (1870-1964), under pressure from the allied forces in the area, crossed the border into Mozambique. Having defeated the Portuguese at the border fortification of Negomano, they would operate in Mozambique for nearly a year, living off the land and what they took from the Portuguese while successfully evading their pursuers. Blamed by their allies for the continuation of the East African campaign, there was little that the Portuguese could do except to try to defend key fortified positions. All strategic initiative lay with the much more mobile Germans, who inflicted a serious defeat on a combined British-Portuguese force at Nhamacurra in July 1918.[10] At the Paris Peace Conference, South Africa’s government would lobby for the transfer of Mozambique to its control, largely on the basis of Portugal’s military missteps.

The War in Europe: Training in Portugal and in Flanders

A possible Portuguese intervention in the European campaign in 1914 was essentially thwarted by the unpreparedness of the country’s army which, already called upon to send expeditions to Angola and Mozambique, was in no position to quickly furnish the full division requested by the British government. Interventionist politicians resolved to create just such a force, to be on hand should the opportunity to go to war again materialize. Their return to power in 1915 allowed Minister of War José Norton de Matos (1867-1955) to take the initial steps for the establishment of an “instruction division”, but this had not yet coalesced by the time Germany declared war on Portugal in March 1916. Portugal’s declaration of war accelerated the process, which concentrated an initial force in Tancos under the command of General Fernando Tamagnini de Abreu e Silva (1856-1924). Two brigades gathered at Tancos, drawn from the eight territorial divisions which together made up the Portuguese army. They underwent some rudimentary and essentially outdated training (with a heavy emphasis on the role of the cavalry) over the course of three months. Although their performance raised a series of red flags in terms of ability and discipline, it was nevertheless hailed as a success by the interventionist press – the process was described as the “Miracle of Tancos” – and the army was pronounced ready to depart for France after a number of visits by foreign dignitaries and a massed parade.[11] The insatiable demand for men to fill the trenches of the Western Front, the determination of Prime Minister Afonso Costa (1871-1937) to send a Portuguese force to France – he argued in London that the failure to do so would result in a political crisis of unforeseeable consequences in Portugal – and French enthusiasm for the venture eventually overrode British doubts about the value of the CEP to the war effort.[12] A coup d’état launched by the disgruntled republican hero António Machado Santos (1875-1921), a naval officer, in December 1916 failed to prevent the CEP’s departure for France, even if some of its supporters within the army’s officer corps refused to lead their men to Lisbon. This led to last-minute changes in personnel and consternation among British observers.

The CEP’s vanguard reached Brest in January 1917. The force initially constituted a single infantry division with supporting artillery and cavalry units. The division had its own commander, and above him stood Tamagnini de Abreu’s autonomous headquarters, created with the expectation that other forces would be sent to France to turn the CEP into a full army corps – as eventually happened later in 1917. There was considerable friction between Tamagnini de Abreu and his chief of staff, Lieutenant-Colonel Roberto Baptista (1874-1932), who had a privileged relationship with Norton de Matos and Afonso Costa. Much of the conflict revolved around the relationship with the British army, which was openly sceptical of the CEP’s contribution. Tamagnini wanted to cooperate as fully as possible; Baptista to defend the Portuguese army’s independence of action. The parameters of this relationship had been established in a convention negotiated by the two countries late in 1916. The CEP initially formed part of General Sir Richard Haking’s (1862-1945) XI Corps, itself part of General Sir Henry Horne’s (1861-1929) I Army. Haking oversaw the second, more focused, stage of the CEP’s training, delayed due to the Portuguese insistence that it should be conducted by Portuguese officers, who first had themselves to be trained by the British. Further delays ensued because the weapons brought from Portugal had to be replaced by British-made weapons, whose arrival and distribution took longer than expected.[13]

The Independent Heavy Artillery Corps

In December 1916, in the aftermath of the Machado Santos coup and as the CEP was preparing for deployment in France, the French government requested the despatch of a large number of trained artillery men to form an independent heavy artillery corps. This unit was to be designed to fight in the French sector, independently of the larger CEP. In response, the Portuguese government called on its largely idle coastal artillery units to make up this force, the advanced guard of which set off for France in May of the following year. The guns they operated were French train-mounted coastal artillery units of different calibres, and the unit, made up eventually of three mixed groups and an independent headquarters, was referred to officially as the Corps d’Artillerie Lourde Portugais.

In February 1918, the personnel of two of these groups was ordered to join the CEP, then in England undertaking training in British artillery. Some of these men would be involved in a mutiny while on British soil, but the rest returned to France after the training period and continued to serve alongside the French army.[14]

The Portuguese Expeditionary Corps at the Front 

Although there were concerns with, among other factors, the health of many of the Portuguese recently arrived in France, training ensued, and existing difficulties were ironed out. Infantry and artillery units began to rotate in and out of the British trenches to gain experience in life at the front. On 30 May 1917, the sector of Ferme du Bois was entrusted to the First Portuguese Brigade; on 16 June, the CEP’s Second Brigade took over the Neuve-Chapelle sector, the Portuguese now holding a full divisional sector of the line. Over the course of the summer, the units that made up the second division began to arrive in France. They too were seasoned in the British trenches before receiving their own sector to defend.

On 26 November 1917, the two divisions were placed side-by-side in the trenches, holding a relatively quiet length of the front line. The interventionist dream had, at long last, come true: there was a Portuguese sector with its own communiqué. But, in reality, the situation was increasingly threatening. Doubts about the CEP’s overall ability were regularly expressed by the British high command, up to and including Sir Douglas Haig (1861-1928). In September, Norton de Matos had rejected a proposal by his British counterpart, Lord Derby (1865-1948), for the insertion of British officers into Portuguese units. He also refused the instalment of the second division as a reserve and training force supporting the first, which was to be included in a British army corps (with Tamagnini de Abreu serving as an inspector of the Portuguese forces). Although no direct link has been found, it is hard to disassociate this growing preoccupation with the CEP’s perceived inability to reform itself from the British admiralty’s decision to stop providing merchant ships and the necessary escorts for the transport of its reinforcements – a decision that greatly hampered this vital task and caused a sense of abandonment among the CEP’s soldiers, as well as a thinning of its ranks through attrition. The British attributed the decision to the Portuguese administrative inability to ensure that space in the ships on the Lisbon-Brest route was utilised optimally.

Operating in a relatively quiet part of the front, in which the Germans dominated what little high ground existed, the CEP was able to fulfil its mission of holding the line. Over time its men learned to coordinate their actions and carried out a number of night-time raids of the German trenches.[15] However, the difficulties faced by the CEP and its commander, General Tamagnini de Abreu, mounted over the course of the winter of 1917/1918.

Meanwhile, the political situation in Lisbon was made decidedly more opaque by the successful coup d’état led by Sidónio Pais, Portugal’s minister in Berlin until Germany’s declaration of war. Hamstrung by the lack of reinforcements, and answering to a government not as committed to the preservation of a Portuguese sector as its predecessor, the CEP’s existing élan and fighting capacity were eroded even as its expertise increased. First one division was withdrawn from the front lines, and then the other, now part of a British army corps and defending the existing Portuguese sector alone, was scheduled to withdraw on 9 April 1918.

Coincidentally, or not, that was the date chosen for the launch of the second of Germany’s Spring Offensives. Identifying a weak point in the British line, the German forces aimed squarely at the CEP. On the morning of 9 April, the exhausted second division, whose men had spent the night preparing to withdraw from the trenches, had little left to give in the face of the massive German onslaught which the Portuguese refer to the Battle of the Lys. Over 6,000 soldiers and officers were captured in the ensuing rout.

After la Lys

After la Lys, the British high command was in no mood to allow the reconstitution of the CEP to take place and was content to use the remaining Portuguese forces as battlefield labourers, a task which necessarily wounded Portuguese pride. It took time for the Sidónio Pais government to react, and the lengthy negotiations undertaken by the CEP’s new commanding officer, General Garcia Rosado (1854-1937), were of little consequence, despite the perseverance with which they were undertaken. Recriminations over responsibility for the defeat also dogged British-Portuguese relations, with the allegation regularly made in the Portuguese press that the British formations flanking the CEP had given ground first, allowing the Germans to surround the Portuguese. Despairing of receiving reinforcements, essential for the reconstitution of the CEP, some of its most committed officers eventually secured permission to return a number of battalions (three are usually mentioned) to the front lines, as independent forces designed to integrate into larger British units. This decision was unpopular with the soldiers and resulted in a number of mutinies, which had to be repressed by force before their return to the trenches. In addition to these infantry battalions there were also a number of light and heavy artillery batteries and other specialised units supporting the British on the front lines when the war came to an end.[16]


Portugal’s armed participation in the First World War was a source of frustration for its people and its allies. Its forces made little contribution to the Entente’s cause, and frequently they provided a scapegoat for allied failures – be it in large battles, such as that of the Lys, or in smaller encounters, such as Negomano and Nhamacurra. The war elevated the profiles of a number of military figures, such as Francisco Aragão (1891-1973), who was captured at Naulila, Carvalho de Araújo, and Óscar Monteiro Torres – usually officers with good republican credentials who battled against the odds and were either killed or made to surrender. However, participation in the conflict was never popular at home and often faced strong opposition among the common people. The sacrifices endured by soldiers and their families were real, of course, and might have tipped the scale in favour of Portugal’s colonial pretensions when, after the war, the country was allowed by Great Britain and France to keep all of its overseas territories. But the hopes of interventionist politicians, who saw warfare as the key to securing and relaunching the embattled republican regime, were dashed. Even the limited exposure to combat which marked Portugal’s belligerence was beyond the country’s ability to sustain solely through recourse to its resources. It is usually estimated that among the fighting forces, both European and African, some 7,000-8,000 men died, mostly in Mozambique and of disease (this total includes porters, for whom records are patchy). In France the number of fatalities stands at close to 2,000. Over 5,000 were wounded in France, while the number of wounded in Africa, hard to estimate, stands at between 600 and 2,300. Some 200 were considered missing in action in France; the number in Africa, especially in Mozambique, rises to the thousands, because it includes porters, most of whom sought to escape whenever possible. Only nine of the missing in Mozambique were European. More significant was the number declared unfit for further military service: over 7,000 in France alone.[17]

Filipe Ribeiro de Meneses, National University of Ireland Maynooth

Reviewed by external referees on behalf of the General Editors