In 1762, at the height of the Seven Years' War, Britain launched one of the most ambitious amphibious operations of the 18th century: a full-scale assault on Havana, the wealthiest and most heavily fortified port in Spain's American empire. The siege lasted more than two months, cost thousands of lives, and ended with the British in possession of an extraordinary haul of treasure, warships, and military stores. Within a few years, the first reported activity on Oak Island would begin. The question that connects the two events is simple: did all of that treasure reach its intended destination?
The Siege
Spain had remained neutral through much of the Seven Years' War, but that changed in 1761 when King Charles III signed the Third Bourbon Family Compact, a secret alliance with France against Britain. When word of the pact reached London, Britain declared war on Spain in January 1762. The response was immediate and devastating. Lord George Anson, First Lord of the Admiralty, and General John Ligonier proposed a strike at Spain's most valuable colonial possession: Havana, the gateway through which the wealth of the Americas flowed on its way to Madrid.
The task force assembled for the operation was enormous. Admiral Sir George Pocock commanded a fleet of roughly 180 vessels, including 22 ships of the line, frigates, sloops, bomb vessels, and transports. General George Keppel, 3rd Earl of Albemarle, led the land forces, which ultimately numbered some 14,000 soldiers drawn from Britain, North America, and the West Indies. Keppel's two younger brothers played key roles: Major General William Keppel commanded troops on the ground, and Commodore Augustus Keppel led a portion of the naval assault. Pocock navigated the fleet through the treacherous Old Bahama Strait from Jamaica, arriving off the Cuban coast on June 6, 1762. Troops landed the following day at Cojimar Bay, six miles east of the city, meeting little initial resistance.
The prize that awaited them was immense. Since the early 1500s, Havana had served as the staging point for Spain's treasure fleets, the convoys that carried silver, gold, emeralds, indigo, cocoa, and Oriental goods across the Atlantic. The city's harbour could accommodate over 100 warships, and its royal shipyard was the finest in the Americas. Defending the harbour entrance was the formidable Castillo de los Tres Reyes del Morro, better known as Morro Castle, perched on a rocky headland and armed with 64 guns. On the opposite side stood the Castillo de San Salvador de la Punta. Between them, a boom chain stretched across the channel. The garrison, under Captain General Juan de Prado, numbered roughly 11,000 men, including regular troops, sailors, marines, and militia.
The Fall of Morro Castle
The Spanish strategy was to delay the British long enough for tropical disease and the approaching hurricane season to do what the garrison alone could not. For weeks, the defenders held. A naval bombardment of Morro Castle on July 1 by HMS Cambridge, Marlborough, and Dragon was beaten back with heavy losses. But the fortress had a critical weakness: the unfortified hill of La Cabaña overlooked its walls, and the British exploited it mercilessly, installing siege batteries that pounded the castle day after day. On July 30, British engineers detonated mines beneath a section of wall, and infantry stormed through the breach. The castle's heroic commander, Luis Vicente de Velasco, had been mortally wounded the previous day; the Spanish navy would name a ship in his honour for generations afterward.
With Morro Castle in British hands, the fall of Havana was only a matter of time. Batteries were positioned along the northern shore of the harbour entrance, and on August 11, a bombardment of 47 heavy guns, 10 mortars, and 5 howitzers opened on the city itself. Fort la Punta was silenced within hours. Captain General de Prado surrendered on August 13, and British forces entered Havana the following day.
The Spoils
The scale of the plunder was staggering. The British seized military equipment valued at 1,828,116 Spanish pesos and merchandise worth an additional 1,000,000 pesos. Some contemporary estimates placed the total value of captured stores and valuables at up to £3 million, an almost inconceivable sum for the period. Nine Spanish ships of the line fell intact into British hands, representing roughly a fifth of Spain's entire naval strength: the Infante, Reina, Soberano, Tigre, Aquilón, San Antonio, América, Conquistador, and San Genaro, along with frigates, sloops, and nearly 100 merchant vessels. Two additional warships under construction in the dockyards were burned.
The division of prize money became a source of lasting bitterness. Admiral Pocock and Lord Albemarle each received £122,697, an extraordinary personal fortune. Commodore Augustus Keppel took home £24,539. The 42 naval captains present each received roughly £1,600. Ordinary soldiers and sailors, by contrast, received approximately £4 each, a paltry sum given the months of brutal fighting, disease, and death they had endured. Of the British forces engaged at Havana, around 1,790 were killed, wounded, or listed as missing in combat, but by October, a further 5,000 had died of tropical fevers. The disparity between the fortunes amassed by senior officers and the scraps handed to the men who actually fought would become a persistent grievance, and it forms the basis of the Oak Island connection.
The Oak Island Theory
The theory linking Havana to Oak Island was most prominently advanced by the late Fred Nolan, one of the island's longest-serving treasure hunters and the discoverer of the stone formation known as Nolan's Cross. Nolan believed that Oak Island's underground workings, including the Money Pit, the artificial beach at Smith's Cove, and the flood tunnel system, were constructed by members of the British military who diverted a portion of the Havana spoils to the island rather than deliver it to the Crown. Author William Crooker further explored this line of reasoning in his book Oak Island Gold, arguing that the treasure was placed on the island for safekeeping and never recovered.
The geographic logic is straightforward. After the siege, captured Spanish vessels and British warships sailed north through waters that pass within easy reach of Nova Scotia. Halifax, the Royal Navy's principal North Atlantic base, lies roughly 1,200 miles from Havana, a voyage of days for a well-crewed warship. Oak Island sits in Mahone Bay, just 60 miles southwest of Halifax, a sheltered location that would have been familiar to any naval officer operating out of the Halifax station. The theory proposes that rogue British officers, resentful of the prize money system that enriched admirals while leaving common sailors with almost nothing, ordered a ship diverted to Oak Island, where the treasure was buried using the engineering skills readily available to military personnel of the period.
Evidence on the Ground
In Season 4, Episode 8 ("The Mystery of Samuel Ball"), metal detection expert Gary Drayton and Oak Island historian Charles Barkhouse explored Lot 24, once part of the property owned by Samuel Ball, a former slave who fought for the British in the American Revolution before settling on Oak Island in 1786 and becoming one of its wealthiest residents. Drayton recovered an 18th-century "dandy button," a copper coin bearing the head of King George II (who reigned from 1727 to 1760), a lead ingot of the type used by British soldiers for casting musket balls, and a metal plate bearing a faded inscription that appeared to come from the stock of a musket. Barkhouse noted that these finds were consistent with Fred Nolan's theory of a British military presence on the island connected to the Havana spoils.
In 1977, Nolan himself discovered a carved stone surveyor's monument in the Oak Island woods while following a survey line. The stone bore chisel scars and scorch marks and had a shape that Nolan compared to a Spanish treasure galleon. While the stone alone proves nothing, Nolan regarded it as further evidence that military surveyors had been active on the island, laying out the kind of precise measurements that would be required for a large-scale construction project like the Money Pit and its flood defences.
The Samuel Ball Question
The Havana theory also intersects with one of Oak Island's most enduring sub-mysteries: the sudden prosperity of Samuel Ball. Born into slavery in South Carolina in 1764, Ball gained his freedom by serving in the British forces during the American Revolution. After the war, he resettled in Nova Scotia and purchased a four-acre lot on Oak Island in 1786, later expanding his holdings to over 100 acres across several lots. Ball grew cabbages commercially, but the scale of his landholdings and the comfortable estate he left behind have long fuelled speculation that farming alone could not account for his wealth. Some researchers believe Ball may have discovered treasure already present on the island, possibly buried by the same British military personnel who had been there decades earlier. Whether Ball's fortune derived from the soil above or something hidden below remains one of Oak Island's unanswered questions.
Strengths and Weaknesses
The Sack of Havana theory has several things working in its favour. The timeline fits comfortably within the period of activity suggested by artifacts and carbon dating on the island, most of which cluster in the late 1600s through the 1700s. The engineering required to construct the Money Pit and its flood tunnel system is consistent with the capabilities of 18th-century British military engineers, who were among the most skilled in the world. The geographic proximity of Oak Island to the Halifax naval base provides a plausible route. And the documented bitterness over prize money distribution offers a motive for diversion.
Its principal weakness is the absence of any documentary evidence. No ship's log, letter, court martial record, or Admiralty file has surfaced linking any vessel from the Havana fleet to Oak Island. The scale of the treasure captured at Havana was enormous, but it was also meticulously inventoried by British officials, making it difficult (though not impossible) for a significant portion to vanish unnoticed. The theory also competes with the earlier timeline suggested by other evidence on the island, including coconut fibre carbon-dated to between 1260 and 1400, the medieval lead cross, and artifacts pointing to activity centuries before 1762. It is possible, of course, that the Havana deposit was a later addition to a site that had already been used for centuries, layered on top of earlier work by different hands. Oak Island's history, if nothing else, seems to be one of multiple visitors across multiple eras, each leaving their mark in the soil.
