A depiction of an episode from the last major operation of the Seven Years War, 1756–63. It was part of England’s offensive against Spain when she entered the war in support of France late in 1761. The British Government’s response was immediately to plan large offensive amphibious operations against Spanish overseas possessions, particularly Havana, the capital of the western dominions and Manila, the capital of the eastern. Havana needed large forces for its capture and early in 1762 ships and troops were dispatched under Admiral Sir George Pocock and General the Earl of Albemarle. The force which descended on Cuba consisted of 22 ships of the line, four 50-gun ships, three 40-gunners, a dozen frigates and a dozen sloops and bomb vessels. In addition there were troopships, storeships, and hospital ships. Pocock took this great fleet of about 180 sail through the dangerous Old Bahama Strait, from Jamaica, to take Havana by surprise. Havana, on Cuba's north coast, was guarded by the elevated Morro Castle which commanded both the entrance to its fine harbour, immediately to the west, and the town on the west side of the bay.

Having landed troops and supplies in early June, 1762, a breach was finally made with mines in the north-east walls of Morro Castle. Here Serres shows a slightly later stage in the attack on the Morro Castle than in a companion picture in the series (in private hands). The red-coated troops, from the main siege camp to the left (east) of the castle are here clearly seen marching in line across the narrow parapet of the transverse wall dividing the catsle's deep dry-ditch defence from the sea and storming up the crumbling rampart into the castle. Over them, explosive mortar shells arc into the castle precinct, all set against a dramatically stormy, lowering sky. The defence of the Morro Castle was ably conducted by Don Luis de Velasco, a veteran Spanish naval officer, who was ordered to replace an ineffective army predecessor after news of the British landing arrived. He was seriously wounded in the final assault and died two days later. However, in recognition of his heroic defence, the head of his family in Spain was ennobled and it was decreed that 'Velasco' be the name of a ship in the Spanish navy.

This is one of a series of pictures painted by Dominic Serres (of which the Museum holds 6 out of 14 identified) to illustrate the principal events of the campaign for the Keppel family, of whom three distinguished brothers served at Havana: George Keppel, 3rd Earl of Albemarle (1724-72) was the army commander-in-chief; Commodore the Hon. Augustus Keppel (1725-86), who was naval second-in-command and Colonel the Hon. William Keppel (1727 -82), who directed the storming of the Morro Castle. The series consists of two groups, six larger paintings with naval emphasis, and five smaller ones (including this) which focus more on the army and the town. It is assumed that the naval ones were painted for Augustus, and the others either for George or William.

The artist Serres knew Havana from his earlier sea-going career and may have lived there for a short period. Before painting these large works for the Keppels, he had previously done a dozen smaller versions which were based partly on sketches by Lieutenat Philip Orsbridge, who had served at Havana. Orsbridge had these engraved by P.C. Canot and James Mason, and published them as a set in 1764-65. Serres's various later versions, including the set for the Keppels,are sometimes close to the prints, but others diverge considerable from them. Serres was a well-born Frenchman from Gascony who ran away to sea in merchant service rather than follow family wish that he enter the Church. He probably arrived in England as a naval prisoner of war, took up painting and settled there. His early paintings show the influence of Brooking and Monamy's interpretations of Dutch art but he rapidly achieved recognition for his more documentary visual accounts of sea actions of the Seven Years War, 1756-63, becoming established as England's leading marine painter. His work was even more in demand in the 1770s and 1780s, recording the naval history of the War of American Independence. In 1768 Serres was a founder member of the Royal Academy and at the end of his life its librarian. A well respected and sociable man, he was appointed Marine Painter to George III in 1780.