Historically, the Municipality of Portel has its origins in the mid-13th century, when, from 1257 onwards, D. João Peres de Aboim, who would also become known as D. João de Portel, came into possession of an extensive area, highlighted of the Municipality of Évora.
The town of Portel was practically born with D. João de Portel, and developed in the shadow of the castle he founded or remodeled by him. Incorporated into the Crown in 1301, during the reign of D. Dinis, the town was later, in 1385, integrated into the lordship of D. Nuno Álvares Pereira. The latter, in turn, donated it, in 1422, to his grandson D. Fernando, and Portel then became part of the heritage of the House of Bragança.