That's Just some of that History please follow link to read the whole story"
Christan Influence:
"Today's Halloween customs are also thought to have been influenced by Christian dogma and practices derived from it. Halloween falls on the evening before the Christian holy days of All Hallows' Day (also known as All Saints', Hallowmas or Hallowtide) on November 1 and All Souls' Day on November 2, thus giving the holiday on October 31 the full name of All Hallows' Eve.[33] "
"By the end of the 12th century they had become holy days of obligation across Europe and involved such traditions as ringing church bells for the souls in purgatory. In addition, "it was customary for criers dressed in black to parade the streets, ringing a bell of mournful sound and calling on all good Christians to remember the poor souls."[36] "Souling", the custom of baking and sharing soul cakes for all christened souls,[37] has been suggested as the origin of trick-or-treating.[38]"
"In parts of Britain, these customs came under attack during the Reformation as some Protestants berated purgatory as a "popish" doctrine incompatible with the notion of predestination. Thus, for some Nonconformist Protestants, the theology of All Hallows’ Eve was redefined; without the doctrine of purgatory, "the returning souls cannot be journeying from Purgatory on their way to Heaven, as Catholics frequently believe and assert. Instead, the so-called ghosts are thought to be in actuality evil spirits. As such they are threatening."[48]"
When It came to North America:
"North American almanacs of the late 18th and early 19th century give no indication that Halloween was celebrated there.[54] The Puritans of New England, for example, maintained strong opposition to Halloween,[54] and it was not until the mass Irish and Scottish immigration during the 19th century that it was brought to North America in earnest.[54] Confined to the immigrant communities during the mid-19th century, it was gradually assimilated into mainstream society and by the first decade of the 20th century it was being celebrated coast to coast by people of all social, racial and religious backgrounds.[55]"
So now some of you have been a little educated to where it began and where it spread to. For the full story please see the link at the beginging. It's quite interesting about the symbolisim and guising. It also goes on to talk about foods and parties.