HistoryData
Historical ConflictGibraltar

Twelfth Siege of Gibraltar

The failed Franco-Spanish siege confirmed Grand Alliance control of Gibraltar, establishing it as a key British naval base in the Mediterranean.

Duration & Scope

1704 1705

1 year

Estimated Total Casualties

10K

Key Facts

Duration
September 1704 – May 1705 (~9 months)
Defender garrison
~2,000 Allied troops
Besieging force
up to 8,000 troops
Franco-Spanish losses
~10,000 men
Grand Alliance losses
~400 men
Naval battles fought
3

Strategic Narrative Overview

Franco-Spanish besiegers numbering up to 8,000 troops surrounded Gibraltar's garrison of roughly 2,000 Allied defenders from September 1704. The defenders exploited Gibraltar's rugged geography and fortifications to repel assaults despite chronic shortages of men and ammunition. French and Spanish commanders were hampered by internal disputes, appalling trench conditions, and epidemic disease. The French navy failed in three naval engagements to sever Allied supply lines, allowing regular reinforcement of the garrison.

01 / The Origins

The Grand Alliance — comprising the Holy Roman Empire, England, the Netherlands, Portugal, pro-Habsburg Spain, and Savoy — sought to prevent the unification of French and Spanish thrones under the Bourbon Philip V. England turned naval attention to the Mediterranean after Portugal joined the alliance in 1703, aiming to disrupt French and Bourbon Spanish shipping and seize a port for use as a naval base. Gibraltar was captured by an Anglo-Dutch force under Sir George Rooke in August 1704.

03 / The Outcome

After nine months of fruitless bombardment, the siege was abandoned in May 1705 following a third decisive naval defeat for France. Franco-Spanish forces reportedly suffered around 10,000 casualties against only about 400 for the Grand Alliance. Gibraltar remained in Allied hands, cementing its role as a strategic Mediterranean naval base and dealing a significant blow to Bourbon ambitions in the broader War of the Spanish Succession.

Belligerents & Mobilization Analysis

Side A

3 belligerents

FranceBourbon SpainIrish Brigade (French service)

Side B

3 belligerents

EnglandDutch RepublicPro-Habsburg Spain / Austria
Key Commanders

Sir George Rooke, Prince George of Hesse-Darmstadt.

Total Casualties (all sides)
10,400
Outcome
Grand Alliance victory; siege abandoned after 9 months; Gibraltar remained under Allied control

Kinetic Engagement Axis

Major engagements timeline (1704–1705)Timeline of major military engagements plotted chronologically.170417051704Naval Battle dur…Side B1704Naval Battle dur…Side B1705Naval Battle dur…Side B

Scroll horizontally to view full axis. Events plotted relatively.

Side A victorySide B victoryInconclusiveDecisive / turning point

Location

Map of Gibraltar, GibraltarMap of Gibraltar, GibraltarGibraltar, Gibraltar