The holy day most call Halloween is known by different names to some. Samhain, or Sow-win; also called Calan Gaeaf by the Welsh, comes from ancient Gaelic people who used this day to mark the beginning of the dark half of the year (November 1st - April 30th). It was customary during the chilly night of October 31st to light a bonfire. The Gaelic people loved fire and used it as part of most holy days. It was also common for families and villages to gather to honor their beloved dead with drunkenness, debauchery, song, oath, and prayer. The bonfires built would also protect the living from the restless dead and Fae spirits who were believed to hunt the lands for souls to take back to the Underworld.
In Italian paganism, we honor this same holy day with the name Tenaebrus or Shadowfest. Many of our traditions are similar to those practiced by Gaelic folk. This is most likely the result of spiritual influence from invading Romans and a concept metaphysicians identify as Collective Consciousness. The one difference seen in the practice of Shadowfest is the encouragement of communication with and hospitality for all dead.
Pagans, both ancient and modern understand the passage from life to death flows both ways. To prevent hauntings and other lingering supernatural activity, the custom of “guising” became common. We do this today when we costume. This prevents spirits from recognizing us. or disguise themselves
The tradition of Trick or Treating came a bit later and is believed to have come from an older practice called 'mumming' where people would travel through the village and countryside guised as spirits and Fae to ask homeowners for small offerings of food and drink. Again this practice was originally done to fool malicious spirits and to honor those who had died in the prior year.