It wasn't Mohammed who founded Islam.

[pocaracas]

And it ignores the earliest references to Muhammad which are recorded even in non-Muslim sources, as I mentioned here with a link.

You know those references, only mention some sort of army general, right?
Here are snippets of the quotes therein:

and in January, they took the word for their lives (did) [the sons of] Emesa [i.e., Ḥimṣ)], and many villages were ruined with killing by [the Arabs of] Muḥammad and a great number of people were killed and captives [were taken] from Galilee as far as Bēth

there was a battle between the Romans and the Arabs of Muḥammad [Syr. tayyāyē d-Mḥmt] in Palestine twelve miles east of Gaza. The Romans fled, leaving behind the patrician YRDN

Then God raised up against them the sons of Ishmael, [numerous] as the sand on the sea shore, whose leader (mdabbrānā) was Muḥammad (mḥmd). Neither walls nor gates, armour or shield, withstood them, and they gained control over the entire land of the Persians.

But not all is bad, there's something slightly reminiscent of a christian gospel. Written by a bishop who maintains that the account of Arab conquests derives from the fugitives who had been eyewitnesses thereof:

At that time a certain man from along those same sons of Ismael, whose name was Mahmet [i.e., Muḥammad], a merchant, as if by God's command appeared to them as a preacher [and] the path of truth. He taught them to recognize the God of Abraham, especially because he was learnt and informed in the history of Moses. Now because the command was from on high, at a single order they all came together in unity of religion. Abandoning their vain cults, they turned to the living God who had appeared to their father Abraham. So, Mahmet legislated for them:[...]

And then you get to Abd al-Malik, the official founder of Islam, right?


So, apart from Sebeos, who's giving us a second hand account (at best) of a leader implementing rules and regulations, you have a military leader.

So... yeah... it is possible there was a military leader behind, at least, some of the arab conquests.... and it is possible such a person's name was Muhamad, or Mehmet, or something similar...
It is also likely that such conquests were done, not by a single army, but by several... well, several battalions, as we'd call them nowadays, huh?
This would give us several military leaders... if you get my drift?...