What period are you talking about in Mecca and Medina?
Hi,
Sorry for this late reply.
I was talking about the era of the Muslim conquests.
As we Shia Muslim don’t recognize the Caliphs of that time (except for Imam Ali) as legitimate caliphs, we have our own view regarding the Conquests. Nonetheless, we don’t give credit to the illegitimate caliphs for spreading Islam.
I am currently writing a booklet about this topic in English
However, this is a big topic and it may take time to finish.
All the best.