HistoryData
Historical ConflictCastillo San Felipe del Morro

Battle of San Juan

The only successful breach and capture of El Morro castle, held by English forces for 65 days before disease forced withdrawal.

Duration & Scope

1598 ongoing

< 1 year

Key Facts

Date of assault
June 15, 1598
English ships
20
English troops
1,700 men
Days held
65 days
English commander
Sir George Clifford, Earl of Cumberland

Strategic Narrative Overview

On June 15, 1598, Cumberland's fleet of 20 ships carrying 1,700 men approached San Juan and overwhelmed the Spanish defenders at the fortress of Castillo San Felipe del Morro. The castle fell, giving England control of the city. English forces occupied San Juan for 65 days, but an outbreak of disease, likely dysentery, steadily reduced the fighting strength of the occupying force and made a sustained occupation untenable.

01 / The Origins

In the late 16th century, England and Spain were engaged in sustained maritime rivalry across the Atlantic. Spain's Caribbean possessions, including Puerto Rico, were valuable colonial assets. English privateers and naval commanders sought to seize or disrupt these holdings. The Earl of Cumberland mounted an expedition in 1598 to capture San Juan, aiming to establish an English foothold and strike a blow against Spanish imperial power in the Americas.

03 / The Outcome

Unable to maintain their hold due to disease casualties, the English forces abandoned San Juan after 65 days. Before departing, they sacked and burned the city. The Spanish subsequently reoccupied the island. England gained no lasting territorial foothold, and control of Puerto Rico returned to Spain. The episode nonetheless marked the only time El Morro's defenses were successfully breached in the colonial era.

Belligerents & Mobilization Analysis

Side A

1 belligerent

Kingdom of England
Peak Mobilized Forces~2K
Forces vs Casualties ratio
0Mobilized
Key Commanders

Sir George Clifford, Earl of Cumberland.

Side B

1 belligerent

Spanish Empire
Outcome
English captured El Morro and San Juan but withdrew after 65 days due to disease; city was sacked and burned before departure

Kinetic Engagement Axis

Major engagements timeline (1598–present)Timeline of major military engagements plotted chronologically.1598present1598Assault on Casti…Allied

Scroll horizontally to view full axis. Events plotted relatively.

Side A victorySide B victoryInconclusiveDecisive / turning point

Location

Map of San Juan, Puerto RicoMap of San Juan, Puerto RicoSan Juan, Puerto Rico