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Historical ConflictAlgeciras

Siege of Algeciras

The failed Castilian siege of Algeciras (1309–1310) demonstrated the difficulty Christian forces faced in seizing this strategically vital port from the Emirate of Granada.

Duration & Scope

1309 1310

1 year

Key Facts

Dates
July 1309 – January 1310
Duration
Approximately 6 months
Result
Castilian defeat; siege lifted
Attacker
Kingdom of Castile
Defender
Emirate of Granada

Strategic Narrative Overview

Castilian forces surrounded Algeciras beginning in July 1309, but the siege dragged on without decisive progress. Conditions in the Castilian camp deteriorated severely, undermining the morale and cohesion of the besieging army. A critical blow came when Infante John of Castile, a powerful vassal, deserted the campaign, depriving Ferdinand IV of essential military and political support needed to sustain the prolonged operation.

01 / The Origins

During the Reconquista, the Kingdom of Castile sought to extend Christian control over southern Iberia by capturing Algeciras, a strategically important port held by the Emirate of Granada. King Ferdinand IV of Castile led the effort, mustering royal forces and vassals to besiege the city. Control of Algeciras would have given Castile a key foothold on the Strait of Gibraltar, threatening Granadan and North African links.

03 / The Outcome

By January 1310, facing wretched camp conditions and the loss of key allies, Ferdinand IV was compelled to abandon the siege entirely. The withdrawal represented a humiliating failure for Castile and left Algeciras in Granadan hands. The city would remain a contested objective for Christian forces in subsequent decades, reflecting its enduring strategic importance on the southern Iberian coastline.

Belligerents & Mobilization Analysis

Side A

1 belligerent

Kingdom of Castile
Key Commanders

Ferdinand IV of Castile, Infante John of Castile.

Side B

1 belligerent

Emirate of Granada
Key Commanders

Abu'l-Juyush Nasr.

Outcome
Castilian defeat; Ferdinand IV lifted the siege due to poor camp conditions and desertion of Infante John of Castile

Kinetic Engagement Axis

Major engagements timeline (1309–1310)Timeline of major military engagements plotted chronologically.130913101309Siege of AlgecirasSide B

Scroll horizontally to view full axis. Events plotted relatively.

Side A victorySide B victoryInconclusiveDecisive / turning point

Location

Map of Algeciras, SpainMap of Algeciras, SpainAlgeciras, Spain