Following the death of King Joao of Portugal in 1494, his son King Manuel I ascended the throne. When his legitimacy as heir to the throne was challenged, Manuel wished to marry Princess Isabel of Spain, daughter of Ferdinand and Isabella, in order to solidify his position. As a precondition to the marriage, the Spanish monarch demanded that Portugal expel its Jews—many of whom were refugees from the 1492 Spanish Expulsion who found refuge in the neighboring country of Portugal. Manuel agreed, and five days after the marriage agreement was signed, on Tevet 23 (5257), he issued a decree giving Portugal's Jews eleven months to leave the country.
Appreciating the Jews' economic value, Manuel was unhappy with the potential loss of this economic asset, and devised a way to have the Jews stay in Portugal—but as Christians. Initially, he instructed the Jews to leave from one of three ports, but soon he restricted them to leaving from Lisbon only. When October of 1497 arrived, thousands of Jews assembled there and were forcibly baptized. Many Jews stayed and kept their Jewish faith secret; they were called Marranos or Crypto-Jews.
Over the next 350 years, the infamous Inquisition persecuted, tortured and burned at the stake thousands of hidden Jews throughout Spain, Portugal and their colonies for continuing to secretly practice the Jewish faith.
Links: The End of Spanish Jewry
Samuel Nunez-Ribeiro—The Life of a Secret Jew
A favorite story of the Rebbe, central to his activist view of life:
Rabbi Schneur Zalman of Liadi, the first rebbe of the Lubavitch dynasty, led the services for Yom Kippur, the holiest day of the year.
He stood wrapped in his prayer shawl, profoundly entranced in the cleaving of his soul to its origin in the Infinite Light. Every word of prayer he uttered was fire. His melody and fervor carried the entire community off to the highest and the deepest journey of the spirit.
And then he stopped. He turned, cast off his prayer shawl and left the synagogue. With a bewildered congregation chasing behind, he walked briskly to the outskirts of town, to a small dark house from where was heard the cry of a newborn infant. The rabbi entered the house, chopped some wood and lit a fire in the oven, boiled some soup and cared for the mother and child who lay helpless in bed.
Then he returned to the synagogue and to the ecstasy of his prayer.
The Rebbe added:
Note that the rabbi removed his prayer shawl. To help someone, you must leave your world, no matter how serene, to enter the place where that person lives.