The issue of aristocracy is one of the most discussed and controversial in Byzantine history because of the scantiness and of the intrinsic ambiguity of most contemporary and later sources: this is probably the main reason why scholars still have not reached a definitive settlement on many of the major topics and questions which concern it. After a short introduction that contains a summary of the historical evolution and of the primary features of Byzantine élites, the essay tries to reconstruct the historiographical debate around the the problem of the lay aristocracy inside the Eastern Roman Empire from the 9th to the middle 15th century. Although we can trace the origins of byzantinology as an independent scholarly discipline at least from the late 16th/early 17th century, a properly ‘scientific’ debate on the questions concerning the aristocracy started only in the second half of the 19th century in the Russian Empire. The aim of the article is to draw a picture of the most prominent historiographic theories and scholars who tackled the issues related to the Byzantine ruling classes from that period onwards. Its core is the analysis of how the historians and their thought influenced or fought each other during one and a half century of academic confrontation and how this rich tradition of scholarly studies led to modern ideas about the Byzantine aristocracy among contemporary byzantinists.