Count of Portalegre (in Portuguese Conde de Portalegre) was a Portuguese title of nobility created by royal decree dated from February 6, 1498, by King Manuel I of Portugal, and granted to Diogo da Silva. Dom Diogo da Silva was son of Rui Gomes da Silva, Alcaide (Mayor) of Campo Maior, and of his wife Isabel de Menezes (natural daughter of Pedro de Menezes, 1st Count of Vila Real). The Habsburgs rewarded this House's fidelity with new honors and titles (Marquis of Gouveia, granted by a royal decree of King Philip III of Portugal, also known as Philip IV of Spain, dated from January 20, 1625).