came under the jurisdiction of the Audiencia of Panama, established in 1533. Spanish domain During the Spanish colonial period the city of Cartagena de Indias was one of the most important ports in America. Enormous wealth in the form of gold from the mines of Colombia was shipped out of Cartagena on established sea routes across the Atlantic to the Spanish ports of Cartagena, Cadiz and Seville. The quinto, or "royal fifth" collected by the Spanish Crown, was needed to finance the gigantic enterprise of conquest, as well as various wars fought by Spain in Europe. The city was also a major center of the trade in enslaved black persons brought from the African continent. In 1536, construction began on the Castillo de San Lázaro, a massive fortress with a series of masonry walls up to 20 meters thick, the most formidable defensive complex of Spanish military architecture to this day. The port was growing in economic importance and strategic value, thanks to the Bay of Cartagena being protected by the Spanish military, as well as its proximity to Panama City, another important Spanish port. In 1538, the Crown authorized the encomienda in the colony; this was a social system that extracted forced labor and tribute from the Indians, whom it deemed "free vassals". The colony was thus converted into a colonial society based on dependency relations with the native peoples. The Spanish Crown attempted to regulate interactions between the Spanish settlers and natives by issuing the Laws of the Indies (Leyes de Indias), while the Catholic Church established the Inquisition to ensure the primacy of the Catholic faith, given the propensity of slaves to follow non-Christian cults that included forms of witchcraft. In the following years, the founder of the colony, Pedro de Heredia, was jailed for crimes against the native people of the Río Sinú valley, including stripping their tombs of the gold objects buried with their dead. and later sentenced to death. Heredia managed to escape to Spain, but died when his ship was wrecked. Cartagena de Indias was assaulted several times by pirates, as well as by French, Dutch, and English privateers, including Francis Drake in 1586. Consequently, King Philip II entrusted Marshal Luis de Tejada and the Italian engineer Bautista Antonelli with the task of building the walls and fortified bastion that defended the city in the 17th and 18th centuries (the fortifications of Castillo