The region of the Amazon valley, by the Treaty of Tordesillas (1494), was in possession of the Spanish Crown, the Portuguese expeditionaries, with the purpose of consolidating the region as Portuguese territory, founded the Fort of the Nativity (Forte do Presépio) in 1616, in Santa Maria de Belém do Grão-Pará (Saint Mary of Bethlehem of the Great Pará). The building was the first of the model on Amazon and the most significant in the Amazon territory until 1660. Despite the construction of fort, the occupation of territory was marked by early Dutch and English incursions in search of spices, hence the need of the Portuguese to fortify the area.