There are many indicators that the name Di Porto may be of Jewish origin, emanating from the Jewish communities of Spain and Portugal.
When the Romans conquered the Jewish nation in 70 CE, much of the Jewish population was sent into exile throughout the Roman Empire. Many were sent to the Iberian Peninsula. The approximately 750,000 Jews living in Spain in the year 1492 were banished from the country by royal decree of Ferdinand and Isabella. The Jews of Portugal, were banished several years later. Reprieve from the banishment decrees was promised to those Jews who converted to Catholicism. Though some converted by choice, most of these New-Christian converts were called CONVERSOS or MARRANOS (a derogatory term for converts meaning pigs in Spanish), ANUSIM (meaning "coerced ones" in Hebrew) and CRYPTO-JEWS, as they secretly continued to practice the tenets of the Jewish faith.Our research has found that the family name Di Porto is cited with respect to Jews & Crypto-Jews in at least 1 bibliographical, documentary, or electronic references:
A bilingual (Portugese/English)reference book of Sephardic surnames. Includes New Christians, Conversos, Crypto-Jews (Marranos), Italians, Berbers and their history in Spain, Portugal and Italy. Contains over 16,000 surnames presented under 12000 entries, with hundreds of rare photographs, family shields and illustrations.It also contains a 72-page summary of Sephardic history, before and after the expulsion from Spain and Portugal, as well as a 40-page linguistic essay about Sephardic names, including an interesting list of the 250 most frequent Sephardic surnames. The period covered by the dictionary is of 600 years, from the 14th to the 20th century, and the area covered includes Spain and Portugal, France, Italy, Holland, England, Germany, Balkans, Central and Eastern Europe, the former Ottoman Empire, Morocco, Algeria, Tunisia, Libya, Egypt, Iraq, Yemen, Syria, Lebanon, Israel, North America, Central America and the Caribbean, South America and more.
Around the 12th century, surnames started to become common in Iberia. In Spain, where Arab-Jewish influence was significant, these new names retained their old original structure, so that many of the Jewish surnames were of Hebrew derivation. Others were directly related to geographical locations and were acquired due to the forced wanderings caused by exile and persecution. Other family names were a result of conversion, when the family accepted the name of their Christian sponsor. In many cases, the Portuguese Jews bear surnames of pure Iberian/Christian origin. Many names have been changed in the course of migration from country to country. In yet other cases "aliases", or totally new names, were adopted due to fear of persecution by the Inquisition.