Battle of San Juan

Background. Spain aligned itself with France by signing the Second Treaty of San Ildefonso in 1796, drawing it into conflict with Britain. The resulting 1796–1808 Anglo-Spanish War provided the setting for a British operation in 1797 targeting the Spanish colonial port city of San Juan in Puerto Rico.

British Arrival. On 17 April 1797, Lieutenant-General Sir Ralph Abercromby's fleet of 68 vessels appeared offshore Puerto Rico with a force of 7,000, which included German auxiliaries and French émigrés. The expedition proceeded to besiege San Juan, the Spanish colonial port city that was its target.

Spanish Counterattacks. The battle was actually a series of successive Spanish attacks on the British siege positions. Further Spanish forces put pressure on the British positions, and the Spanish recaptured Martín Peña Bridge, undermining the siege the British had established around San Juan.

Díaz Raids Behind British Lines. While Spanish forces pressed the British positions, the militia led by José "Pepe" Díaz (1776 – April 30, 1797) and Sergeant Francisco Díaz (1777 – ?), both cousins, raided behind British lines, bringing back prisoners. These Spanish countermeasures broke the British force and the siege of San Juan by it.