Christian mercenaries hired by Muslim rulers in 13th century, Christian church in northern Africa

Check out the article by Michael Lower in the Speculum issue of July 2014. Lower discusses the family tradition of some Muslim rulers in hiring Christian mercenaries to fight their battles in the 13th century. this is in northern Africa. There is even a North African Christian church established and the papacy continued to send mendicant friars to preach there through the 13th century. It's hard to say what kind of status these mercenaries held in Islamic lands. Perhaps as an elite fighting force for the ruler like the Varangian Guards in Constantinople? Don't know, but Lower discusses these men fighting in Morocco, Fez, the Maghrib and Marrakesh.