Complex sentence: The "El Salvador" sailed from Cartagena, Colombia for Cadiz, Spain loaded with a cargo of gold and silver, where she was part of the Spanish treasure fleet, which was a convoy system adopted by the Spanish Empire from 1566 to 1790.
Split into simpler sentences: The "El Salvador" sailed from Cartagena, Colombia for Cadiz, Spain loaded with a cargo of gold and silver. She was part of the Spanish treasure fleet which was a convoy system adopted by the Spanish Empire from 1566 to 1790.