Forced Labor in Construction of Colonial Fortifications (1539-1790s)

The fortifications of San Juan — today celebrated as UNESCO World Heritage Sites and major tourist attractions — were built through centuries of forced labor under Spanish colonial rule.

Construction Timeline:
- 1539: Construction of La Fortaleza begins — the first major fortification
- 1539-1589: Initial construction of Castillo San Felipe del Morro (El Morro)
- 1634-1641: Construction of city walls begins
- 1634-1790s: Castillo San Cristóbal built and expanded over 150+ years
- 1765-1783: Major expansion under Field Marshal Alejandro O'Reilly and military engineer Tomás O'Daly

Who Built Them:
- Enslaved Africans: The primary labor force for the heaviest construction work. Enslaved people quarried limestone, mixed morite, carried materials, and performed the most dangerous tasks. Many died from exhaustion, accidents, and disease.
- Convict labor (presidiarios): Prisoners from across the Spanish Empire were sent to Puerto Rico to work on fortifications. Some were political prisoners.
- Conscripted locals: Taíno, mestizo, and poor criollo men were conscripted into labor gangs (corvée labor)
- Military labor: Soldiers of the garrison also performed construction work, often in brutal conditions
- Paid artisans: Some skilled masons and carpenters were paid, but they supervised forced laborers

Scale of the Project:
- El Morro's walls are up to 18 feet thick and 140 feet above sea level
- San Cristóbal covers 27 acres — the largest fortification built by the Spanish in the Americas
- The city walls extended over 3 miles
- Millions of cubic feet of limestone, sandstone, and earth were moved by hand

Colonial Purpose:
The fortifications were not built to protect Puerto Rico — they were built to protect Spain's colonial trade routes. Puerto Rico's strategic position guarding the Mona Passage made it essential for defending Spanish treasure fleets returning from Mexico and South America. The island's people were conscripted and enslaved to build defenses for an empire that extracted their labor and resources.

Today, millions of tourists visit these fortifications with little awareness that they were built by enslaved and forced laborers — a common pattern in the sanitization of colonial history.