The origin of Halloween varied reasons for its existence. in the fifth Century BC Celitc lreland officially ended summer on October 31.The summer's end, which was also called Samhain, marked the end of the harvest season. One story states that on that day spirits of those who had died throughout the preceding year would be free to look for living bodies to possess for the next year. Thus, in order to frighten away the spirits, people derssed in all manner of costumes and noisily paraded around the neighbourhood.