There's an entire section about religions being an amalgamation of thousand year old beliefs.
Here's a section. Horus was an Egyptian god, born on dec 25th to the virgin Isis Mary, accompanied by a star in the east and adored by 3 kings. He was a prodigal child teacher at 12, baptized at 30, had 12 disciples, and performed miracles (healing sick, walking on water). After being betrayed by Tython (?), he was crucified, dead for 3 days and then resurrected.
There's a lot more in there about positions of the stars and what not.
https://historyforatheists.com/2016/12/the-great-myths-2-christmas-mithras-and-paganism/ This site has a great breakdown and take down of the most popular atheist "myths" about religion. Religious stories and arguments collapse on their own lack of merits; there's no need to make up bad history to try to debunk or discredit them. Movies like Zeitgeist are not helpful, and if anything end up poisoning the well by making objections to religion look weak and fallacious.