Answer:
The ethnic group that left Europe in the years before 1948 to escape persecution and discrimination were Jewish people. This migration, known as the Jewish diaspora, was largely driven by the rise of anti-Semitism in Europe and culminated in the establishment of the state of Israel in 1948. Jewish people faced discrimination and persecution in many European countries, particularly in Eastern Europe where pogroms (violent attacks against Jewish communities) were common. This, combined with the atrocities of the Holocaust during World War II, led many Jewish people to seek a new life in other parts of the world, including the United States, Israel, and other countries.