What factors contributed to the success …

Islamic decoration and architecture is very similar to the Byzantine Empire as well. The heavy use of marble and gold mosaics. The important of covering a woman's skin up and veiling her in Islam came directly from the Byzantine Empire. Poetry was also hugely impacted in Islam by Byzantine. These early caliphates, coupled with Muslim economics and trading, the Islamic Golden Age, and the Age of the Islamic Gunpowders, resulted in Islam's spread outwards from Mecca towards the Indian, Atlantic, and Pacific Oceans and the creation of the Muslim world. One reason was to spread the Islamic faith throughout the world. They were successful in the Sassanid region (and beyond), but only partially successful in the Byzantine Empire and later in Western Europe. Land grab and war booty. These were weak (Rome and Sassanids) and right for a grab.