My source. The first few pages of chapter one have some great information!

One quote pulled here is "Wherever there were courts, there were elite groups to serve them. Some of these Umayyad elites were former Byzantine and Sasanian officials who had recast themselves to serve new masters. Others were Umayyad kinsmen, whose private estates dotted the countryside. Still others were leaders of the Arab tribes that migrated to Syria even before the Islamic conquests." This quote is from page 2. Keep in mind this is a very simplistic overview of Umayyad elites who served on courts.

The quote here is saying if you were an Arab leader that didn't put up a fight, a kinsmen of the Umayyad or former officials from the Byzantine and Sasanian empires who "recasted" themselves to fit in you could be on some sort of court. The people on these courts were some of the elites.