Morteira was a student of prominent Italian rabbi
Leon de Modena. In a Spanish poem
Daniel Levi de Barrios speaks of him as being a native of
Germany ("
de Alemania natural"). From the age of thirteen, Morteira accompanied
Elijah Montalto to
Paris and served as his secretary at the
Louvre until 1616. When Montalto died, Morteira escorted the body of the physician from France to Amsterdam, where a Jewish community had been openly established and he could have a Jewish burial. In Amsterdam he married a poor Jewish orphan, whose dowry was provided by a Jewish charity for poor women. This marital pattern was typical for rabbis in Amsterdam at the time. Rabbis were not desirable candidates for marriage into rich Sephardi families. The fact that Morteira was from Venice and not a Sephardi Jew might have also been a factor, despite his eminence as a rabbi. The Sephardic
Congregation Beth Jaacob ("House of Jacob") in Amsterdam elected him
hakham in succession to
Moses ben Aroyo. Morteira was the founder of the congregational school Keter Torah, in the highest class of which he taught
Talmud and
Jewish philosophy. He was the senior rabbi when the three Amsterdam congregations merged in 1639, outranking
Menasseh Ben Israel, and receiving an annual remuneration of 600 guilders. The two rabbis had strong differences of opinion. Morteira was fiercely anti-Christian, while Ben Israel sought to bridge the religious divide between Jews and Christians, particularly dissenting Protestants. Their feuding prompted the intervention of the ''
Ma'amad'', the political arm of the community, to prevent the rabbis' disputes from becoming open and a source of instability in the congregation. Among his most notable pupils were
Moses Zacuto,
Abraham Cohen Pimentel, and
Baruch Spinoza. Morteira was concerned about members of the congregation violating Jewish law and questioning rabbinic authority. He instigated an investigation against physician Daniel de Prado (also known as Dr. Juan de Prado, born in Andalusia c. 1614), who held deist beliefs, and Daniel de Ribeira, a Catalan convert to Judaism, then apostate from it. Both "held a deprecatory and cynical view of the Law of Moses", doubted the divine nature of Scripture, and argued against the immortality of the soul. Their views influenced Spinoza. Morteira and
Isaac da Fonseca Aboab (
Manasseh ben Israel was at that time in England) were members of the ''Ma'amad
which on 27 July 1656 pronounced the decree of cherem'' (excommunication) against Spinoza. ==Works==