In the south, Ecuador had ''de jure'' claims to a small piece of land beside the Pacific Ocean known as Tumbes which lay between the Zarumilla and Tumbes rivers. In Ecuador's southern Andes Mountain region where the Marañon cuts across, Ecuador had ''de jure'' claims to an area it called Jaén de Bracamoros. These areas were included as part of the territory of Gran Colombia by Bolivar on December 17, 1819, during the Congress of Angostura when the Republic of Gran Colombia was created. Tumbes declared itself independent from Spain on January 17, 1821, and Jaen de Bracamoros on June 17, 1821, without any outside help from revolutionary armies. However, that same year, 1821, Peruvian forces participating in the Trujillo revolution occupied both Jaen and Tumbes. Some Peruvian generals, without any legal titles backing them up and with Ecuador still federated with the Gran Colombia, had the desire to annex Ecuador to the Republic of Peru at the expense of the Gran Colombia, feeling that Ecuador was once part of the Inca Empire.