Easter is the most important solemnity (just before Christmas) of the Church. It is the first of the five cardinal feasts of the Catholic liturgical year. Easter commemorates the resurrection of Jesus Christ laid down by the Bible, the third day after his passion. The solemnity begins on Easter Sunday, which for Catholics mark the end of fasting of Lent, and lasts for eight days (Easter week, or week or radiant, or week of eight Sundays).
Many customs dating back to ancient times designed to accommodate the return of spring attached themselves to Easter. The egg is the symbol of germination occurs in early spring. Similarly, the hare is an ancient symbol which has always represented fertility.