1831 naval engagement between France and Portugal
The Battle of the Tagus was a naval engagement that took place on 11 July 1831 at the mouth of the Tagus river, in Portugal. A French fleet attacked and subdued Portuguese fortifications at the entrance of the Tagus, with the aim to strong-arm the government of Miguel I into recognising the newly established Kingdom of the French. The damage to the forts defending access to the Tagus and the arrival of French warships at Lisbon forced the Portuguese to cave in and comply with French demands.
Background.
The accession of King Miguel I to the throne of Portugal and abolition of the Constitutional Charter had put the country under the rule of an absolutist monarch. Liberals challenged his rule, and the struggle of the Liberal Wars ensued. The government of Miguel I was hostile to France, and became even more so when the popular insurrection of the July Revolution deposed the absolutist Bourbon king Charles X, and established a constitutional monarchy in which Louis-Philippe had become "King of the French". Miguel refused to recognise the Monarchy of July, while neither the French nor the British government recognised his.
In early 1831, a French citizen, Edmond Potentin Bonhomme was sentenced to public flogging, a fine and exile for allegedly profaning a church, a claim that French officials dismissed as "they had good reason to believe that many of the statements it comprehends, have no other foundation than the bigotry and malevolence of the Portuguese priesthood". Several other French citizen were similarly detained in what the French government judged to be arbitrary manners.
The French consul in Lisbon, Cassas, was tasked to present a diplomatic demarche to the Portuguese government, but he was rebuffed as not having the diplomatic credentials of an ambassador. Viscount d'Asseca requested a mediation of the British Foreign minister, Viscount Palmerston, who advised the Portuguese to comply with French demands. A squadron under Captain de Rabaudy, comprising the 60-gun frigate "Melpomène" and the 20-gun brig "Endymion", under Nonay, was sent to the mouth of the Tagus river to show the flag and give weight to the demands of the French consul. They arrived on 16 March 1831. Upon her departure from Brest, "Melpomène" ran aground on Basse Beuzec, and had to double back, leaving " Endymion" to continue her route. When "Melpomène" finally arrived on 16 May 1831, " Endymion" was already returning to France, with the consul aboard. Rabaudy stated the purpose of his mission to Portuguese authorities and delivered the French ultimatum, demanding:
These demands had to be met 48 hours after reception.
Portuguese authorities played for time. In consequence, Rabaudy's "Melpomène" started blockading Lisbon by preying upon shipping leaving and entering the Tagus, though their crew were immediately freed and sent ashore. "Melpomène" was soon reinforced by a squadron under Captain Charmasson, of the 52-gun "Sirène", escorted by the 18-gun corvettes "Diligente" and "Églé", and the 20-gun brig "Hussard". While some of the ships cruised off the mouth of the Tagus, the others were detached to Azores to hunt for a Portuguese Miguelist division that blockaded the Liberal controlled Terceira Island; on 3 June, these ships captured the 24-gun corvette "Urania" and the 6-gun fluyt "Oreste", but they failed to locate the rest of the Miguelist forces, and thus returned to the mouth of Tagus.
In spite of the French blockade and their undermining of its war effort against Liberals, the Portuguese government refused to meet French demands, and the treatment of the French prisoners even deteriorated. The French therefore decided to escalate the matter, and Henri de Rigny, French Minister of the Navy, appointed rear-Admiral Baron Albin Roussin to a 6-sail of the line squadron. Roussin was a veteran of the Mauritius campaign of 1809–1811, and had been honoured for his conduct at the Battle of Grand Port.
Battle.
The mission of Rear-admiral Roussin was to sail to Tagus, with his flag on the 90-gun "Suffren", and give the Portuguese authorities an ultimatum that demanded, in addition to that already given by Rabaudy, that the chief of the Portuguese police be dismissed; that all court sentences against French citizens be annulled; and that indemnities be paid to compensate for the costs induced by the expedition. The ultimatum expired 48 hours from reception, at which point the French forces would force the entrance of the Tagus, sail to Lisbon and bombard the city. Departed from Brest, the squadron arrived off the Tagus on 25 June, and stayed there waiting for the division inbound from Toulon, under Rear-admiral Hugon.
On 31, the Portuguese government mobilised the warship on the Tagus, though only two frigates and smaller warships could be marshaled at once; the strongest asset on Tagus, the 74-gun "Dom João VI", needed over a month of work worth of repairs, and the 52-gun frigate "Amazona" could not be readied before twenty days. This left only the 54-gun "Diana"
and the 44-gun "Pérola", with the 26-gun "Dom João I" and "Lealdade", to oppose the much stronger French squadron. In addition, all the ships that the Portuguese could muster were much under-handed. The condition deteriorated on 1 July when "Suffren" and "Melpomène" chased the "Lord Wellington", a Portuguese merchantman inbound from Bahia; "Lord Wellington" fled under Fort Santo António to benefit from its protection. When the French ship approached, the fort opened fire, and a gunnery exchange broke out while the ships' boats were launched and captured the merchantman. The French bombardment silenced the fort, killing five or six soldiers, and severely wounding thirty.
On 6, Hugon's squadron arrived from Toulon. Being forced to inaction by unfavourable winds, Roussin attempted a last diplomatic demarche and on 10, he sent the 18-gun brig "Dragon", under Commander Théodore Deloffre, to present a last ultimatum; "Dragon" also carried letters for the ships of the Tagus and for foreign diplomatic missions in Lisbon, and was under strict orders not to remain at anchor more than 24 hours. The new ultimatum comprised the same condition as the first, but added that the Portuguese government should compensate France for the price of the naval expedition, and threatened of a "de facto war". "Dragon" returned to the French fleet the next day with a refusal, though Santarem attempted to surrender his French prisoners to the British as a token concession. Captain Vincent Moulac, of "Algésiras", advised that the fleet attempt to force the entrance of the river and sail upstream to Lisbon.
On 11, the winds had turned, and a North-North-West wind allowed for the expedition upstream. The French squadron manoeuvred to form a line of battle, and at 13:30, it sailed into the Southern pass. The French squadron sailed one by one in front of the forts, delivering broadsides at distances varying from 100 to 1000 metres, and reached Paço de Arcos in good order and with no serious damage. Roussin signaled his ships to sail on, but the two lead ships, "Marengo" and "Algésiras", failed to spot the signals and dropped their anchor, as was initially planned to repair damage sustained during the forcing of the pass; seeing that the flagship "Suffren" sailed before them without stopping, they promptly put to sail and took a place in the French line, but this mistake put "Suffren" at the front of the line.
Around 16:00, "Suffren" opened fire on the Belém Tower at a distance of 100 metres, soon followed by the rest of the squadron, and anchored in front of the Belém Palace while the other ships and frigates sailed on to the anchored Portuguese fleet. When the lead ship, "Pallas", opened fire on the Portuguese squadron, all its ships struck, without firing a shot.
By 17:00, the entire French squadron was anchored before the docks of Lisbon, and Roussin sent his chief of staff, Lieutenant commander Charles Ollivier, to present the French ultimatum once again with a 2-hour delay. The Portuguese government attempted once again to turn its prisoners over to British officials, but the offer was once again refused. The Portuguese government caved in, and a treaty was signed on 14 July on "Suffren" by Castello Branco and Roussin, with its dispositions published in the "Lisbon Gazette" on 15, and the sums of money begin paid in cash by the 23. With the ultimatum accepted by the Portuguese, Roussin sent most of the squadron to sea, staying in front of Lisbon with only "Suffren", "Pallas" and "Melpomène"; the 58-gun frigate "Guerrière", under Captain Kerdrain, rejoined him on 29.
Squadrons.
Key
Aftermath.
The treaty of 14 July specified that the French would return the ships captured before the attack on the Tagus, including the warships "Orestes" and "Urania" and the merchantmen with their cargo. After a council of war on "Trident", the French decided to also return the captured 74-gun "Dom João VI" as, being neither armed nor manned during the action, she did not belong to an opposing force.
Nothing was said, however, of the fleet captured at Lisbon itself. The Portuguese government protested, and Roussin proposed that the ships be re-purchased for 1.5 million cruzados, or to return half the captured ships, in exchange for the release of 400 political prisoners. When this offer was rejected, the ships in question were incorporated in the French fleet.
The French squadron of Toulon departed on 25; the prizes "Diana", "Amazone", "Don João I" and "Don Pedro" departed with on 12 with a brig, and the next day "Perola", "Lealdade", "Saint Sebastian" and "Memoria" followed. The rest of the fleet eventually departed for Brest on 14 August, where it arrived on 4 September, leaving only "Melpomène" and "Églé".
In recognition for the deed, Roussin was promoted to Vice-admiral.
The Miguelists would suffer a crushing defeat at the hands of the Liberals at the Battle of Cape St. Vincent two years later, ending the reign of Miguel I.
Notes and references.
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