How to increase zeal as a Muslim faction?

[Knight Templar]

In Catholic lands, zeal is also important for inquistion; higher the zeal, inquisitor has more chances to succee

[miho]

Is zeal in anyway important to the Orthodox cultures?

[NodachiSam]

Good question. I don't really think it is past great zeal making the populace less loyal.

It would be curious to know if higher zeal also made the populace convert to you faster as I imagine highly zealous people are a little less tolerant and would perhaps persecute and forcibly convert less fortunate outnumbered minorities.

[Ludens]

Is zeal in anyway important to the Orthodox cultures?

No. Zeal's main effects are on crusades/jihads and inquisition, and neither of those is important to the Orthodox.

There is however the loyalty effect: high zeal provinces will dislike low piety governors and low zeal provinces are don't want high piety rulers. I also think, like geezer57 said, that high zeal will make them more likely to revolt against a ruler of a different faith (high zeal Catholic provinces don't like excommunicated rulers either), but I cannot confirm this with certainty. However, obtaining high zeal is almost impossible for an Orthodox ruler, unless you happen to have zealot or related vices. But I have only seen those vices appear in governors of high zeal provinces, so...

[miho]

It would be curious to know if higher zeal also made the populace convert to you faster as I imagine highly zealous people are a little less tolerant and would perhaps persecute and forcibly convert less fortunate outnumbered minorities.

I think it would be the opposite. High zeal Christians would logically convert harder to another religion.