Is there such a thing as a ‘Christian art’ or ‘Muslim art’ style?  A highlight of Cairo for me [Jacob] was seeing ‘Christian art’ and ‘Muslim art’ break out of the standard stereotypes. Take a look at some of the following images:

“God is Love” in Arabic calligraphy above the entrance to an ancient coptic church built on Roman ruins

 another piece of arabic calligraphy inside the church

arabesque geometric designs derived from the double cross, a standard Coptic symbol for Christ.
 wandering inside Al-Azhar Mosque (the oldest in Cairo and academic center of Islam), I noticed these stained-glass windows.  It doesn’t fit the stereotypes for mosques.  At the formative early stage of ‘Islamic’ art and architecture’s history, the patrons and sponsors were Muslim rulers, but the actual artisans, craftsmen, artists and artisans were mostly Christian.  In most of the Christian world, this has been forgotten, but the architecture and manuscripts from Egypt show that Christians felt this art form was a integral part of their heritage. 
 This illumination from a 14th century Coptic gospel contains the Great Commission (Mt 28:18-20) in Arabic calligraphy

 Most of the Coptic (Egyptian Christian) manuscripts begin with ‘bismillah’ (‘In the name of Allah’) as part of their tradition
 Another coptic manuscript illumination with arabic calligraphy in the Kufic style
from a Coptic gospel, this geometric design is based on the eight-armed cross

I think this was an arabic manuscript of a John Chrysostom’s commentary on scripture