Halloween was first celebrated over two thousand years ago by the ancient Celts, who believed that at this time the veil between this world and the other world was thin enough for the spirits of the dead to cross over and walk among us.Religious Tolerance: The Myth of Samhain

• 1,000-100 B.C.: The Celts celebrate Samhain on November 1st, painting faces on gourds and their own faces to scare away spirits

• 600 A.D.: In an effort to stop the pagan celebrations, Pope Boniface IV designates November 1st All Saints' Day

• 800 A.D.: Pope Gregory III declares that villagers may dress in costume as saints, and young men must go door to door to beg for food for the poor

• 1500s: Samhain and All Saints' Day become All Hallows' Day, the night before, All Hallows' Evening, Hallow Evening, or Hallowe'en

• 1600s: Considering them Catholic holidays, New England Puritans ban Halloween, Christmas and Easter

• 1840s: The Irish Potato Famine brings Irish Catholics to America, along with their Halloween traditions. Due to the abundance of pumpkins, they carve them into jack o'lanterns instead of turnips

• 1860s: Members of the Catholic and Episcopalian churches campaign to officially sanction Halloween

• 1870: Halloween becomes a popular holiday, along with the idea of "tricking", an excuse to cause mischief

• 1912: The Dennison Manufacturing Co. of Framingham, Massachusetts publishes Halloween "Bogie" books that include party and decoration ideas and Halloween costume patterns

• 1918: Most Halloween celebrations are canceled due to the Spanish Flu Pandemic

• 1921: Anoka, Minnesota becomes the first American city to officially sanction a citywide Halloween celebration

• 1923: New York begins citywide Halloween celebrations

• 1924: Anaheim, California holds its first Halloween parade

• 1925: Los Angeles begins citywide Halloween celebrations

• Present: Halloween is a 2.5 billion dollar industry