How did Halloween start and why?

It started with the ancient Celtic festival of Samhain, when people would light bonfires and wear costumes to ward off ghosts. ... Over time, Halloween evolved into a day of activities like trick-or-treating, carving jack-o-lanterns, festive gatherings, donning costumes and eating treats.

Explanation:

the american revolution was by the middle and upper class, and the french was by the lower and middle class.

i confess that there are several parts of this constitution which i do not at present approve, but i am not sure i shall never approve them: for having lived long, i have experienced many instances of being obliged by better information or fuller consideration, to change opinions even on important subjects, which i once thought right, but found to be otherwise. it is therefore that the older i grow, the more apt i am to doubt my own judgment, and to pay more respect to the judgment of others.