(albeit the Bahai are persecuted violently).
Yet a couple months ago, there were rumors of Christian conversions in Iran, partly because of the increase of "religious police" going against those merely having fun. One podcast had James Dunnigan of Strategy page remarking that Iran, prior to Islam, was not Christian (as was Iraq and Syria) but Zorastrian, and Islam there still includes a lot of Zorastrian customs and festivals. He quipped that many people, in disgust at the fundamentalist crackdown, might just revert to Zorastrianism too.
So today's StrategyPage has this note:
June 1, 2008: Despite keeping a low profile, the growing number of Christian converts are being hunted down and arrested. The religious police try to persuade the converts to return to the Islamic fold, reminding them that apostasy (converting from Islam to another religion) is forbidden by the Koran and punishable by death. However, the Iranian constitution allows apostasy, so the government shows some restraint. But since the Islamic clerics took control of the government three decades ago, several hundred non-Moslems have been executed, and thousands more imprisoned or harassed. Most Iranians are willing to tolerate other religions (and there are over a dozen such minorities in Iran, including several that pre-date Islam, and one that was developed in the 19th century.)