Hesychius synthesized his lexicon primarily from the lost second-century compilation of Diogenianus of Heraclea.

In his epistolary preface to Eulogius, Hesychius states that his work, titled Synagoge pason lexeon kata stoicheion, expands upon the alphabetical lexicon of Diogenianus of Heraclea. Diogenianus had integrated separate specialized dictionaries covering Homeric, tragic, comic, and lyric vocabulary, alongside medical and historical terms. Hesychius augmented this compilation with glosses from Cyril of Alexandria, Homeric proverbs, and rare dialectal variants, preserving fragments from otherwise lost classical Greek authors.