http://en.wikipedia.org/wiki/Crescent http://www.fotw.net/flags/islam.html That explains quite a bit too
many religious symbols and practices stem from pagan times. before christianity the cross was used as a symbol, with the four points of the cross symbolising the elements, earth, wind, fire, water. and the star used in the star of david predates judaism as a potent pagan symbol for use in mystical ceremonies, though it would usually be encircled. and because many pagans worshipped goddesses, with the birth of christianity the figure of the virgin mary was specifically used to wean such worshippers off pagan idols and onto a more suitable icon. the christmas tree and holly wreaths are also a reminder of our pagan past, in particular the winter solstice celebrations when people would eat dried fruits and drink mead, and gather holly and other evergreens as a sign of continued fertility and the bounty of mother nature.