When Portugal Bombarded a U.S. Warship to Protect a Confederate Ironclad!

At 10:00 am on March 28, 1865, the Confederate ironclad Stonewall weighed anchor and proceeded out of Lisbon, Portugal, seeking to cross the Atlantic. Seeing the ironclad leaving, Commodore Thomas Craven ordered USS Niagara to likewise raise its anchor. The commander at Belem Tower, the fortification guarding Lisbon’s entrance, took this as an attempt to chase Stonewall out of port, a violation of the 24-hour rule of customary international naval law that required a full day between belligerents departing neutral ports from one another. To ensure Niagara remained in port, Belem’s commander ordered his guns manned, opening an accurate fire that one Niagara sailor observed: “One shot st[ruck] us forward of the Beam and an[other] struck our smokestack and sever[al] pass[e]d over us.”[1]

Belem Tower fires on USS Niagara (Harper’s Weekly, May 13, 1865)

The United States Civil War occurred at a time of little tangible recorded international law, but a host of customary international legal expectations. The only international laws in existence were agreements signed by numerous international partners, though these were only binding to the signatories. A great example is the 1856 Paris Declaration governing blockades, neutral rights of transportation in wartime, and outlawing privateering by its signatories (though not the U.S. and thus also not the Confederacy). There were also two rules collectively called the 24-hour rules. One said that belligerent warships entering a neutral port could remain only for 24 hours to necessitate emergency repairs or procure necessary supplies (not contraband of war). Captains could petition to remain if repairs would take longer. The second 24-hour rule was that one belligerent warship could not depart a neutral harbor until 24 hours after their enemy’s ship did. This was to prevent belligerents from fighting an engagement in neutral waters.

A host of countries declared their neutrality in the U.S. Civil War or issued statements that since they signed the 1856 Paris Declaration, privateers from either the United States or Confederacy were prohibited from bringing captures into their ports. Among these were Great Britain, France, Prussia, Belgium, the Netherlands, Spain, Portugal, Brazil, Hawaii, Bremen, and Hamburg.[2] British orders to the Admiralty highlight the extent of such neutrality directives. Regarding the length of time belligerents could remain in a British port, the Admiralty was instructed that “such vessel shall be required to depart and to put to sea within twenty-four hours after her entrance into such port, roadstead, or waters, except in case of stress of weather, or of her requiring provisions or things necessary for the subsistence of her crew or repairs.”[3]

Similarly, regarding when belligerents could leave British ports, the Admiralty was instructed “If there then shall be ships of war or privateers belonging to both the said belligerents within the territorial jurisdiction of Her Majesty, in or near the same port, roadstead, or waters, the Lieutenant Governor shall fix the order of time in which such vessels shall depart. No such vessel of either belligerent shall be permitted to put to sea until after the expiration of at least twenty-four hours from the time when the last preceding vessel of the other belligerent (whether the same shall be a ship of war, or privateer, or merchant-ship), which shall have left the same port, roadstead, or waters, or waters adjacent thereto, shall have passed beyond the territorial jurisdiction of Her Majesty.”[4]

Both 24-hour rules were in effect during the U.S. Civil War. When USS Iroquois entered the French port of Saint-Pierre, in Martinique, in November 1861, it found CSS Sumter docked there. After anchoring, French officials boarded Iroquois, informing its captain the U.S. warship “should, according to International Law, remain twenty-four hours after the departure of the Sumpter [sic].”[5] Instead, Iroquois immediately weighed anchor and took station outside the port, forcing Sumter to instead remain in port for another day and hoping they would catch the Confederate raider when it attempted to leave. The wily Raphael Semmes ultimately managed to sneak past Iroquois to open sea. Two years later, USS Kearsarge patrolled outside French territorial waters so CSS Alabama could legally depart Cherbourg and meet its fate in ship-to-ship combat.

CSS Stonewall, photographed at Ferrol, Spain, just before arriving in Lisbon, Portugal (Naval History and Heritage Command)

When Captain Thomas Jefferson Page brought CSS Stonewall into Lisbon, he was instructed by Portuguese officials to “leave the port without delay.”[6] Similarly, when USS Niagara, accompanied by USS Sacramento, reached Lisbon after chasing Stonewall there, Commodore Craven was instructed by port officials to “anchor where I then was about half a mile to the eastward of the Tower of Belem, and not attempt to go out of the harbor until twenty-four hours had elapsed after the departure of the Stonewall.”[7]

Late 19th Century Image of Belem Tower (Library Congress)

It was the violation of this 24-hour rule that caused Belem Tower to fire on USS Niagara. From the perspective of that fortification’s commander, CSS Stonewall was legally departing Lisbon and USS Niagara was illegally following. Thus, soldiers inside Belem Tower, “famous for its political prisoners in times past,” manned their guns and according to Niagara’s logbook, “the fort opened on us and fired nine shots.”[8] Niagara immediately turned and dipped its colors as a sign to cease fire and that it was not leaving port. No sailors were hurt in the bombardment.

USS Niagara (US Naval History and Heritage Command)

In fact, Commodore Craven insisted he never intended to leave port, but instead was just shifting Niagara’s berth “to the usual place of mooring vessels of war, which is more convenient for intercourse with the city.”[9] To do so, Craven insisted, he had to first depart his original anchorage and steam for the mouth of Lisbon Harbor, as if he were departing, before turning Niagara for its new position. To the commodore, it was a misunderstanding that caused Belem Tower to open fire. This, Craven was fine with, but Belem fired a second salvo after Craven “immediately ordered our flag to be dipped or hauled part way down, as a signal that his warning was understood.”[10]

Commodore Thomas Craven, USN (Naval History and Heritage Command)

To Commodore Craven, this second salvo was an insult and violation of Portuguese neutrality. Belem Tower’s commander believed the second salvo ensured his enforcing Portuguese neutrality. Regardless of whether Craven was repositioning in the harbor or trying to chase Stonewall, the cannonade might quickly burst into a major international incident. To appease the United States and halt any chance of diplomatic escalation, Belem Tower’s commander was relieved, the local governor replaced, and the fort fired a twenty-one-gun salute “in honor of the flag of the United States” while a U.S. flag flew from its ramparts and USS Niagara, with Commodore Craven aboard, looked on.[11]

So, as CSS Stonewall crossed the Atlantic to ultimately be trapped in Cuban waters, USS Niagara oversaw the official apology that allowed both Portugal and the United States to officially forget that a Lisbon fort fired on a U.S. warship to protect a Confederate ironclad.[12] It remains a forgotten, but curious, incident, all because of customary international law regulations called the 24-hour rules.



[1] William Gould IV, ed., Diary of a Contraband: The Civil War Passage of a Black Sailor (Stanford, CA: Stanford University Press, 2002), 233.

[2] The text of neutrality declarations from Great Britain, France, Prussia, Belgium, the Netherlands, Spain, Portugal, Hawaii, Bremen, and Hamburg can be found in Montague Bernard, A Historical Account of the Neutrality of Great Britain During the American Civil War (London: Longmans, Greene, Reader, and Dyer, 1870), 135-150. For Brazil’s neutrality, see Nathan L. Ferris, “The Relations of the United States with South America during the American Civil War,” The Hispanic American Historical Review, Volume 21, Number 1 (February 1941), 54.

[3] J. Russell to the Admiralty, January 31, 1862, Bernard, A Historical Account of the Neutrality of Great Britain During the American Civil War, 139.

[4] Ibid, 138.

[5] Edward W. Bacon, Diary Entry, December 9, 1861, George S. Burkhardt, ed., Double Duty in the Civil War: The Letters of Sailor and Soldier Edward W. Bacon (Carbondale, IL: Southern Illinois University Press, 2009), 25.

[6] Thomas J. Page, “The Career of the Confederate Cruiser ‘Stonewall’”, Southern Historical Society Papers (Richmond, VA: The Southern Historical Society, 1879), Volume 7, 275.

[7] Thomas Craven to Gideon Welles, March 29, 1865, Official Records of the Union and Confederate Navies in the War of the Rebellion [hereafter ORN], Series 1, Volume 3, 461.

[8] Lawrence J. Bopp and Stephen R. Bockmiller, eds., The Civil War Diary of Moses Safford, USS Constellation, (Charleston, SC: The History Press, 2004), 27; Abstract log of March 28 for USS Niagara, ORN, Series 1, Vol. 3, 465.

[9] James E. Harvey to the Duke De Loulé, March 29, 1865, ORN, Series 1, Volume 3, 478.

[10] Thomas Craven to James E. Harvey, March 28, 1865, Ibid, 477.

[11] James E. Harvey to Thomas Craven, April 8, 1865, Ibid.

[12] For more about Stonewall’s journey see Neil P. Chatelain, “A Series of International Incidents: The Transatlantic Odyssey of the Confederate Ironclad Stonewall,” TRAVERSEA, Volume 5, 2015, 45-61.

2 Responses to When Portugal Bombarded a U.S. Warship to Protect a Confederate Ironclad!

  1. An excellent article! These kind of ‘naval/international’ evidences and incidents are vastly under-used and so informative.

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