17 Shevat

1420- Purim Saragossa (or Siracusa) was established because of a miracle in the Jewish community of Saragossa, Spain where the Jews were miraculously saved. Saragossa Purim commemorates the miracle that occurred when an apostate slandered the Jews.

He told the king that the Jews were going to honor him by parading about with empty sifrei Torah cases, having left the holy scrolls in the Aron Kodesh. That night, Eliyahu Hanavi appeared to the shamash and warned him to return the holy scrolls to their cases, warning him to tell no one of his dream. The next day, when the king checked and found that the information was false, he killed the apostate and the Jews were saved.

The Jews of Saragossa decided to observe the 17th and 18th days of Shvat as days of prayer and joyous thanks to the Almighty, so that their children and future generations would remember the story of how they had been miraculously saved from destruction at the hands of a cruel enemy. Some sources date this miracle in 1440.