Happy Halloween. Here is some of the origins of Halloween, rallygirl. Sleepy Hollow was a result not really an origin.
Many of the ancient peoples of Europe marked the end of the harvest season and the beginning of winter by celebrating a holiday in late autumn. The most important of these holidays to influence later Halloween customs was Samhain, a holiday observed by the ancient Celts. Among the Celts, Samhain marked the end of one year and the beginning of the next. It was one of four Celtic holidays linked to important transitions in the annual cycle of seasons.
Samhain began at sundown on October 31 and extended into the following day. According to the Celtic pagan religion, known as Druidism, the spirits of those who had died in the preceding year roamed the earth on Samhain evening. The Celts sought to ward off these spirits with offerings of food and drink. The Celts also built bonfires at sacred hilltop sites and performed rituals, often involving human and animal sacrifices, to honor Druid deities.
Then the Romans conquered most of the Celtic land, big surprise there, and took in some of their customs adding in some of their own such as worshipping the goddess of fruit trees which some how lead to bobbing for apples.
The Roman Catholic Church often incorporated modified versions of older religious traditions in order to win converts. One Pope sought to replace Samhain with All Saints' Day in 835. All Souls' Day, closer in spirit to Samhain and modern Halloween, was first instituted at a French monastery in the year 997or somewhere close to that and quickly spread throughout Europe. Folk observances linked to these Christian holidays, including Halloween, thus preserved many of the ancient Celtic customs associated with Samhain.
Europe had witch hunts in the 15 and 17th centuries and the witches and black cats were added to Halloween tradition.
The jack-o-latern was originally from Scotland and was really a turnip not a pumkin.
Okay there is mostly everything you never needed to know about Halloween courtesy of one of my teacher's love of Halloween. Delete if you want, I don't care. History is interesting, but for Halloween all that really matters is fun and candy.