Sephardic knowledge of the language and culture of the enemy, their skills as diplomats and professionals, as well as their desire for relief from intolerable conditions — the very same reasons that they had proved useful to the Arabs in the early stages of the Muslim invasion — made their services very valuable. However, the Jews from the Muslim south were not entirely secure in their northward migrations. Old prejudices were compounded by newer ones. Suspicions of complicity with the Muslims were alive and well as Jews immigrated, speaking Arabic. However, many of the newly arrived Jews of the north prospered during the late 11th and early 12th centuries. The majority of Latin documentation regarding Jews during this period refers to their landed property, fields, and vineyards. In many ways life had come full circle for the Sephardim of "al-Andalus". As conditions became more oppressive during the 12th and 13th centuries, Jews again looked to an outside culture for relief. Christian leaders of reconquered cities granted them extensive autonomy, and Jewish scholarship recovered somewhat and developed as communities grew in size and importance. However, the Reconquista Jews never reached the same heights as had those of the Golden Age. Among the Sephardim were many who were the descendants, or heads, of wealthy families and who, as "Marranos", had occupied prominent positions in the countries they had left. Some had been state officials, others had held positions of dignity within the Church; many had been the heads of large banking-houses and mercantile establishments, and some were physicians or scholars who had officiated as teachers in high schools. Their Spanish or Portuguese was a lingua franca that enabled Sephardim from different countries to engage in commerce and diplomacy. With their social equals they associated freely, without regard to religion and more likely with regard to equivalent or comparative education, for they were generally well read, which became a tradition and expectation. They were received at the courts of sultans, kings, and princes, and often were employed as ambassadors, envoys, or agents. The number of Sephardim who have rendered important services to different countries is considerable as Samuel Abravanel (or "Abrabanel"—financial councilor to the viceroy of Naples) or Moses Curiel (or "Jeromino Nunes da Costa"-serving as Agent to the Crown of Portugal in the United Provinces). Among other names mentioned are those of Belmonte, Nasi, Francisco Pacheco, Blas, Pedro de Herrera, Palache, Pimentel, Azevedo, Sagaste, Salvador, Sasportas, Costa, Curiel, Cansino, Schönenberg, Sapoznik (Zapatero), Toledo, Miranda, Toledano, Pereira, and Teixeira.