What is the origin of the Mormon Temple Ceremony and how has it changed throughout the years?

I understand that there is a difference between being a Mormon and being a Temple Mormon (one who has gone through the Temple Ceremony at least once and maintains Temple worthiness). I also understand that it is quite similar to the Masonic Temple Ceremonies and that Joseph Smith was himself a mason. Where exactly, then, did this Temple Ceremony come from? Has it changed throughout the years and, if so, how specifically has it changed?