On November,24th or 25th, 2014 among many other coins a special coin will be auctioned by the Geneva auction house Numismatica Genevensis SA, which is said to be minted in the years 679-691 and is of great historical interest.
The coin can be seen at the following website
http://www.sixbid.com/browse.html?auction=1609&category=33779&lot=1442255It shows on the front side a crowned ruler with cross insignia, on the reverse side an M (to indicate the currency value of the coin), which also carries a cross, below is unmistakably to be read "m-h-m-d" in Arabic script, ie Arabic "muhammad" (or Aramaic "mahmad"). The scripture on the front is probably not to be read as "[Banu] Nu'man", as the auctioneer reads, but as a "bi-'amman", "in Amman", indicating the city where the coin was minted.
This combination of a Christian prince with the title "muhammad", "highly praised" again makes clear that the conventional narrative of the foundation of Islam by some Muhammad in Mecca is dubious. This story rather originates from later (Abbaside?) times.