During the Middle Ages, the fate of Jews in various parts of Italy was an alternation between prosperity and persecution. There were expulsions from Bologna in 1172 and from Trani in 1380. Under Norman rule, the Jews of southern Italy and Sicily enjoyed greater freedom. They were considered the equals to Christians and were allowed to choose any career; they even had jurisdiction over their own affairs. A later pope—either Nicholas IV (1288–1292) or Boniface VIII (1294–1303)—had for his physician a Jew, Isaac ben Mordecai.
The Holy Roman Emperor, Frederick II, commissioned Jews to translate philosophical and astronomical treatises from the Arabic.
The position of Jews in Italy worsened considerably under Pope Innocent III (1198–1216). He threatened those who placed or maintained Jews in public positions with excommunication and commanded that every Jew holding office should be dismissed. He also postulated that every Jew must wear a conspicuous yellow badge. In 1235, Pope Gregory IX published the first bull against the ritual murder accusation. Other popes followed his example, particularly Innocent IV in 1247, Gregory X in 1272, Clement VI in 1348, Gregory XI in 1371, Martin V in 1422, Nicholas V in 1447, Sixtus V in 1475, Paul III in 1540, and later Alexander VII, Clement XIII, and Clement XIV.
The Jews suffered from the relentless persecutions of the Avignon-based “antipope” Benedict XIII. They welcomed his successor, Martin V. The synod convoked by the Jews in Bologna and Forlì sent a delegation with lavish gifts to the new pope, pleading for the abolishment of the oppressive laws promulgated by Benedict. The delegation succeeded, but the period of grace was short; Martin’s successor, Eugenius IV, at first favorable to the Jews, ultimately reissued all of Benedict’s restrictive laws. His bull was mostly disregarded in Italy. Here, in the larger cities such as Venice, Florence, Genoa and Pisa, commercial interests prevailed over the affairs of the Church; accordingly, the Jews, many of whom were bankers and merchants, prospered.
The Jews were also known as skilled medical practitioners, and through their services as physicians they were often able to negotiate restrictions and civic rights. William of Portaleone, physician to King Ferdinand I of Naples, and to the houses of Sforza and Gonzaga, was one of the most respected of that time.