Zoroastrianism questions

[TheRealJoeFish]

So, it's clear from further reading on the subject that Zoroastrianism was the dominant religion from around northern Iraq to Armenia at some point before 200 BCE. It would be very odd indeed for Zoroaster to be the figurehead of a religion in 200 BCE but to not have religious teachings attributed to him until 300 CE. It's similarly difficult to believe, in the absence of further explanation, that people in 300 CE selected Zoroaster, who had lived 1000 to 2000 years prior, and imputed christianity's teachings to him.

This christian may be technically correct, inasmuch as we don't appear to have fragments of writing, detailing Zoroaster's religious claims, that were created BCE. However, people had been worshiping Zoroaster and following Zoroastrianism for hundreds of years at that point; surely, they were worshiping/adhering to some sort of religious claims. Would it be impossible for Zoroastrianism to have been influenced by Christianity? Nah, it probably was. But the strong money's on a more significant flow of ideas in the other direction.

In short, Zoroastrianism's still a valid counterexample when someone claims christianity is omg-so-original-that-it-must-be-true-because-no-one-ever-thought-of-that-stuff-before!!!1!

ETA: There's also a record of leaders during the Parthian Period (roughly 220 BCE to 250 CE) actively seeking a consolidation and codification of teachings that, as Justtristo says, had been passed down orally for many centuries, with the job not being finished until those Sassanians got in on the act.