Fortifications on the Caribbean Side of Panama: Portobelo-San Lorenzo
The group of 17th- and 18th-century fortifications, the historic sites of Portobelo and San Lorenzo, are outstanding examples of Spanish colonial military architecture of this period. These fortifications, imbued with history, are a magnificent example of Spanish military architecture, located in a natural setting of great beauty.
The forts, castles, barracks and batteries of Portobelo created a defensive line around the bay and protected the harbour; the works at San Lorenzo guarded the mouth of the Chagres River. Conquered by Henry Morgan in 1668 and by Admiral Edward Vernon in 1739, these fortifications were continuously rebuilt because they command the access to the Isthmus of Panama, which has always been of the utmost importance for Europe's commerce with its colonies. In 1761 the Spaniards rebuilt the fort for the third time, building the structures seen today. However, trade routes had changed and the new fort did not suffer any new attacks.
Antonelli's Spanish military architecture characterizes the first construction period (1596-99) and the neoclassical style of Salas and Hernandez (1753-60) dominated afterwards.
The Pan American Institute of Geography and History, along with other international organizations, already recognizes the sites of Portobelo and San Lorenzo El Real to be of universal importance; they are an essential link to an understanding of American history. The forts are however in a poor state of preservation.
Fort San Lorenzo was abandoned by Spain in 1821 when Panama became independent. After Panama became part of Colombia, the fort was used as a prison, then as the point of entry for mail from Britain to Latin America. During the California Gold Rush in 1849 it served as a camping ground for adventurers, particularly on the old town of Chagres below the fort and on the west bank of the Chagres River. The Chagres River stayed as the main inter-ocean route until the construction of the railroad from Manzanillo Island (now Colón City) to Panama in 1850.