If there is one thing that the Church hates it's a Pagan Festival which is why they tried so hard to replace them with their own Festivals but not only did they copy and paste their own people into Christmas and Easter but they also did their best to replace the original Halloween with their own.
Around 2000 years ago the ancient Celtics held the festival of Samhain to celebrate their new year on November 1 and believed that on the night before the new year, the boundary between the worlds of the living and the dead became blurred and the ghosts of the dead returned to Earth.
Along came the invading Romans circa 43 A.D. who attempted to combine Samhain with their own festival of Feralia when the Romans commemorated the passing of their dead.
Many of the traditions of Halloween came from this period with concern that they would encounter returning ghosts if they left their homes so would wear masks to avoid being recognised by the dead and so that the ghosts would mistake them for fellow spirits.
To keep ghosts away from their houses, people would place bowls of food outside their homes to appease the ghosts and prevent them from attempting to enter.
To finally usurp the Celts the Catholic Church renamed 1 November as All Soul's Day around 1000 AD to honour all the dead including Christian Saints and Martyr's and the original Halloween was replaced with a related church-sanctioned holiday and another Pagan Festival was consigned into the dustbin of History by a Church desperate to erase all traces of anything that didn't celebrate it and it's beliefs.