The Celtic festival known as Samhain is believed to be the predecessor of modern Halloween. Samhain marked the end of the Celtic harvest season. It was also the start of the Celtic New Year. The date for the New Year was October 31. On this day, the Celts believed that the lines separating the living and the dead dissipated.
During this time, evil spirits were said to roam the Earth. To combat these forces, the Celts would don masks. This aspect in the history of Halloween helps explain the tradition of watching scary costumes during the festival.
When
The Germans made it official in the early 1900s, but the first celebrations of it date back to about 40 AD.
Traditions
Traditions include going trick or treating, which is dressing up and going door to door saying trick or treat to get candy, also there is pumpkin picking patches, drinking hot cider, going on hay rides, and of course HAVING FUN!
Extra
Some strong christian believers do not celebrate this holiday, because to them it is known as the "devils holiday",
instead for people who do not celebrate halloween they will go to church, and have there own harvest kind of fun,
minus the gory and scary stuff.
Disclaimer
I do not own any information or pictures posted on here unless stated otherwise, all information has been redistributed from different websites.