Islam not so successful?

[Gurroruo]

So what if Islam wasn't so successful and didn't conquer vast amounts of land? What needs to happen for this to occur?

 

[Lalli]

Depends how far Islam then would spread. But if we want keep Islam staying only in Arabia, best way would be that we somehow avoid multiple wars between Byzantine and Persia so both empires could be much stronger, but not so strong that they could conquer Arabia. But even then Islam can spread via sea routes.

 

[jahenders]

1) Mohammed dies before things are really spread or documented

2) The Mongols go as far as Mecca/Medina and destroy everything

3) As noted elsewhere, Byzantium and Persia are both stronger when Islam arises so it's not largely filling a power vacuum

4) Far more recently, Western Powers (or the Ottomans) get/retain control of most of the oil/oil revenues. Without the money from oil, modern Islam (especially jihadi-type) isn't nearly as well funded, advertised, documented, etc.

 

[Blackfox5]

The expansion of Islam was driven by the desire to gain booty as much as it was to spread the word. Between Mohammed's death and the Muslim conquests, there was actually a huge war in Arabia. Mohammed was a successful war leader and had attracted the other Arabs to his banner, but when he died many of those groups and tribes abandoned the religion and went back to doing their own thing. They either abandoned Islam entirely or set up their own prophet. This lead to the Ridda Wars where the Muslims fought to bring those other tribes together. Support for the actual religion was much less than the success of Mohammed's diplomacy and war leadership.

Given the factors of the Arab bedouin life, the Muslim leadership had to direct the bedouin tendency to raiding outward to prevent the nascent Arab state from collapsing. Their success as war leaders and providing the Arabs with loot and pillage was critical. It was to the advantage of the Muslims that they had a great military leader like Khalid.

If the Muslims fail to defeat the Byzantines and Persians, then the factors keeping the Muslim Arab coalition together cease to exist. The nascent Muslim state will collapse. Islam will likely retain some power and authority in the Hedjaz, but the Arabs in other parts of the peninsula will likely go apostate.

Islam will likely be restricted to a small group and eventually be seen as a strange Christian heresy. It will only revive if another superb war leader skilled in diplomacy is able to recreate the Arab coalition and once again attack (and this time defeat) the existing empires. As Byzantium and Persia recover and regain their strength, this is much more unlikely than in the period of the Muslim conquests.

I would pick the most likely POD for an early Muslim military defeat is a different Battle of Yarmouk which leads to a defeat of the Muslims instead of the Byzantines. An early enough defeat will be a severe blow to their military prospects.