Sea of Faith - Islam and Christianity in the Medieval Mediterranean World (Stephen O'Shea, 2006)

This was a very helpful follow-up to related books described here and here and here and here.

O'Shea builds the story around seven key battles involving Christianity and Islam around the Mediterranean during the middle ages.

Poiters in 732 (only 110 years after the hejira).

Baghdad was a new city in 762 - supplanting Damascus.

Spain is really complex - interaction between Islam, Christianity, Jews; always a bit geographically removed.

"Horns of Hattin" - effectively ending Crusader states in 1187.

And Constantinople "falls" in 1453.