In An Account of the Manners and Customs of the Modern Egyptians written in Egypt during the years 1833-1835 (1836) Edward William Lane noted, and illustrated with his own woodcuts, his close observations of the Rifa'i derwishes while living in Cairo "in disguise".
The "disguise" was by no means superficial and necessitated a variety of resources in linguistics and social integration that left marks far beyond the mere popular success of travelogues.