What is Zoroastrianism ?

I've heard about it but i dint know anything about it, help ?

A dualistic predecessor to Judaism and Christianity. There were supposedly two Gods. Ahura Mazda and Angra Mainyu. Mazda was good and more powerful like God, and Angra was evil and less powerful like Satan.

A religion that believed in a good god and a bad god that predates Christianity, mainly practiced today in parts of Iran. It's prophet, Zoroaster, or Zarathustra revealed the religion in 6000 BCE.

Here's a piece from the NYT:
http://www.nytimes.com/2006/09/06/us/06faith.html

"In Iran, after Muslims rose to power in the seventh century A.D., historians say the Zoroastrian population was decimated by massacres, persecution and conversions to Islam. Seven boatloads of Zoroastrian refugees fled Iran and landed on the coast of India in 936."

(Side note: that is what would have happened to Christianity had it not been for the Crusades:

"Without the Crusades, it [Christianity] might well have followed Zoroastrianism, another of Islam?s rivals, into [virtual] extinction.? -- Dr. Thomas Madden, professor of History and Crusades scholar
http://www.natcath.com/NCR_Online/archives2/2006a/022406/022406a.php )