In the summer of 1796, Pedro Maria Gonzalez, a surgeon trained at the College of Cadiz, took part in an expedition commissioned by the Cadiz Consulate with the aim of initiating trading relationships with Smyrna, the most important commercial centre in the Ottoman Empire. On his return, he wrote a document to facilitate future business ventures by Spaniards, describing in detail the customs and traditions of the various social and ethnic groups that inhabited the city of Smyrna. In this paper, I analyse the view of the Turks held by Europeans in the 17th and 18th centuries and the ideological and conceptual factors underlying their negative opinions. I then describe the viewpoint of Gonzalez himself, especially in relation to Jews, the ethnic group he studied in greatest depth. The fact that they shared a common language, Spanish, undoubtedly facilitated his relationships and his close analysis.