The most obvious link between modern and ancient Greeks is their language, which has a documented tradition from at least the 14th century BC to the present day, albeit with a break during the Greek Dark Ages (lasting from the 11th to the 8th century BC).[155] Scholars compare its continuity of tradition to Chinese alone.[155][156] Since its inception, Hellenism was primarily a matter of common culture[43] and the national continuity of the Greek world is a lot more certain than its demographic.[157] Yet, Hellenism also embodied an ancestral dimension through aspects of Athenian literature that developed and influenced ideas of descent based on autochthony.[158] During the later years of the Eastern Roman Empire, areas such as Ionia and Constantinople experienced a Hellenic revival in language, philosophy, and literature and on classical models of thought and scholarship.[157] This revival provided a powerful impetus to the sense of cultural affinity with ancient Greece and its classical heritage.[157] The cultural changes undergone by the Greeks are, despite a surviving common sense of ethnicity, undeniable.[157] At the same time, the Greeks have retained their language and alphabet, certain values and cultural traditions, customs, a sense of religious and cultural difference and exclusion, (the word barbarian was used by 12th-century historian Anna Komnene to describe non-Greek speakers),[159] a sense of Greek identity and common sense of ethnicity despite the global political and social changes of the past two millennia.