 After the discovery of the Americas, Seville became the economic centre of the Spanish Empire as its port monopolised the trans-oceanic trade and the Casa de Contratación (House of Trade) wielded its power.As navigation of the Guadalquivir River became increasingly difficult, Seville's trade monopoly was lost to Cádiz.The construction of the canal known as the Corta de Merlina in 1794 marked the beginning of the modernisation of the port of Seville.