In the middle ages, Jews had largely been regarded as adherents to the Law of Moses in contrast to a focus on their different ethnic or linguistic origins. Their faith distinguished them from Christians who expressed faith in Christ or in Muslims who followed the teachings of Mohammed. Las Siete Partidas is a law code written in Castilian and was compiled around 1265, under the direction of King Alfonso X, the Wise (1252-1284) of Castile. It did not go into effect until 1348, however.
The Laws on Jews, 1265 Title XXIV: states,
“Jews are a people, who, although they do not believe in the religion of Our Lord Jesus Christ, yet, the great Christian sovereigns have always permitted them to live among them…LAW I. What The Word Jew Means, and Whence This Term is Derived.” A party who believes in, and adheres to the law of Moses is called a Jew, according to the strict signification of the term, as well as one who is circumcised, and observes the other precepts commanded by his religion. This name is derived from the tribe of Judah which was nobler and more powerful than the others, and, also possessed any other advantage, because the king of the Jews had to be selected from that tribe, and its members always received the first wounds in battle. The reason that the church, emperors, kings, and princes permitted the Jews to dwell among them and with Christians, is because they always lived, as it were, in captivity, as it was constantly La token] in the minds of men that they were descended from those who crucified Our Lord Jesus Christ.” 
While there were exceptions, a Jewish convert to Christianity regardless of Levitical or priestly lineage was theoretically viewed simply as a Christian after their religious transformation. An example of an exception can be found in the requirement that Jewish converts to Christianity from the Barcelona Jewish community were obligated to provide Jewish witnesses in lawsuits that involved Christians and Jews. As Alexandra Guerson notes,
“Baptism had not as Christian teaching says, made of the convert truly a ‘new man,’ even in the king’s own perception, not to mention that of his legal advisors.”
In the aftermath of the violence in 1391, the Crown continued to deal with Conversos of the island of Majorca in a manner that was similar to how the king had treated Jews. This reality, in addition to other financial obligations of the Converso community, reinforced the connections Conversos maintained with one another and insured that they remain rooted in the same social and economic condition they had when they were officially Jewish. As a consequence, this helped to insure that the identity of the Conversos in Majorca would be attached to their past as a Jewish community. This would in turn foster continued aspects and characteristics of Jewish identity.  A notable exception is the case of Pope Anacletus II (1130-1138) whose great grandfather was Jewish. Anacletus served as a cardinal for years without any disapproval because of his Jewish ancestry. When he was elected by a majority of the College of Cardinals to serve as Pope, however, Bernard of Clairvaux, a prominent preacher raised Anacletus’ Jewish background as a reason to oppose him.
 Jacob Marcus, The Jew in the Medieval World: A Sourcebook, 315-1791, (New York: JPS, 1938), 34-42. See also Fernando Suárez Bilbao, Cristianos Contra Judíos y Conversos, (Universidad «Rey Juan Carlos», Madrid, 2004), 446.
 Alexandra Guerson “Seeking Remission: Jewish Conversion in the Crown of Aragon, c. 1378-1391” Jewish History (2010): 38.
 Fernando Suárez Bilbao, Cristianos Contra Judíos y Conversos, (Universidad «Rey Juan Carlos», Madrid, 2004), p. 446. Natalie Oeltjen, “Crisis and Regeneration: The Conversos of Majorca, 1391 – 1416.”(Ph.D. diss., University of Toronto, 2012), 41.
 Salo Wittmayer Baron, A Social and the Religious History of the Jews: Volume IV ( Philadelphia: Jewish Publication Society, 1957), 10-11.
Posted by Rabbi Dr. Juan Marcos Bejarano Gutierrez the director of the B’nei Anusim Center for Education. For a more complete review of Iberian Jewish history and the Crypto- Jewish Experience see Conversos and the Sabbatean Movement, The Rise of the Inquisition and Secret Jews: The Complex Identity of Crypto-Jews and Crypto-Judaism