Medieval Genoa had a cosmopolitan character. The presence of western Muslims is understandable in view of the contacts since the 11th century. They can be observed at a diplomatic level, become manifest in the presence of translators or writers for Arabic documents (third quarter of the 13th century, p. 122-23) and of traders. However, most Muslims in Genoa were slaves. Their names show that Christianization was more successful with female slaves than with males. Between 1159 and 1280, Jehel identifies around 100 persons (p. 124).

With regard to the Jews the tradition is poorer and partly questionable (for example, people having Christian forenames wore epithets like “Judeus”). A source of 1134 fixed the tax to be paid by them (3 s. to the cathedral of S. Lorenzo). Many came from the Provence, some from Naples, Gaeta and Tortosa and can be identified via trading activities. Besides economic relations, relations on an intellectual field can also be ascertained: Arabic manuscripts and writings on Christian-Jewish relations are extant in Genoese libraries.