Would there be a Thanksgiving if Christ wasn't born?

I was called a moron for saying that there wouldn't be a Thanksgiving if it weren't for Christ's birth. I was always told that the Pilgrims came to America to free religious persecution and what not, so technically since the whole reason the Pilgrims even came here was because of religion and Christ, Thanksgiving would not have originated if it weren't for Christ's birth? Thanksgiving wouldn't have happened the way it did without Jesus being born so therefore, there wouldn't have been the Thanksgiving we know today, correct? Would there have been Thanksgiving without Christ's birth?