The initial settlement, named Villa de la Santísima Trinidad, was founded in 1514 by Diego de Velázquez on a site settled by the Taíno. The Spanish conquistadores found the native Indians panning for gold in the nearby rivers. The Spanish established a lucrative (but short-lived) gold mine that lent vigor to the young township and the wharves of nearby Casilda. Hernán Cortés set up base in 1518 to provision his expedition to conquer the Aztec empire. Soon fleets bearing the spoils of Mexico gathered, bringing new prosperity and eclipsing Trinidad’s meager mines.
Trinidad  was just far enough from the reach of Spanish authorities in Havana  to develop a bustling smuggling trade. Its position on Cuba’s underbelly was also perfect for trade with Jamaica, the epicenter of the Caribbean slave trade.
Trinidad grew prosperous importing slaves, many of whom were put to work locally, stimulating the sugar trade. Money poured in from the proceeds of sugar grown in the Valle de los Ingenios . When the English occupied Cuba, in 1762–1763, Trinidad became a free port and prospered even further, entering its golden age.
Wealthy citizens built their sumptuous homes around the main square—Plaza Mayor—and along the adjoining streets. Pianos from Berlin; sumptuous furniture from France; linens, lattices, and silverware from Colombia were unloaded here. Language schools and academies were even set up to prepare the children of the wealthy to complete their studies in Europe. The city’s wealth drew pirates. Many citizens prospered as victualers to the sea-roving vagabonds, while some pirates bought property and settled.
By the early 19th century, Cienfuegos , with its vastly superior harbor, began to surpass Casilda, which had begun silting up. Trinidad  began a steady decline, hastened by tumult in the slave trade and new competition from more advanced estates elsewhere in Cuba. Isolated from the Cuban mainstream, Trinidad foundered. By the turn of the 20th century, it was a down-at-the-heels little town.
In the 1950s, Batista declared Trinidad  a “jewel of colonial architecture.” A preservation law was passed. Development was prohibited and the city continued to stagnate in its own beauty. The construction of the Carretera Central on the north side of the Sierra Escambray  had already stolen the through traffic, ensuring that Trinidad would be preserved in its past. The town was named a national monument in 1965. A Restoration Committee was established, and the historic core around Plaza Mayor has been completely restored. In 1988 UNESCO named Trinidad a World Heritage Site.