The Suda or Souda is a large 10th-century Byzantine encyclopedia of the ancient Mediterranean world, formerly attributed to an author called Soudas or Souidas. It is an encyclopedic lexicon, written in Greek, with 30,000 entries, many drawing from ancient sources that have since been lost, and often derived from medieval Christian compilers. The derivation is probably from the Byzantine Greek word souda, meaning "fortress" or "stronghold", with the alternate name, Suidas, stemming from an error made by Eustathius, who mistook the title for the author's name.

Content and sources

The Suda is somewhere between a grammatical dictionary and an encyclopedia in the modern sense. It explains the source, derivation, and meaning of words according to the philology of its period, using such earlier authorities as Harpocration and Helladios. It is a rich source of ancient and Byzantine history and life, although not every article is of equal quality, and it is an "uncritical" compilation.
Much of the work is probably interpolated, and passages that refer to Michael Psellos are deemed interpolations which were added in later copies.

Biographical notices

This lexicon contains numerous biographical notices on political, ecclesiastical, and literary figures of the Byzantine Empire to the tenth century, those biographical entries being condensations from the works of Hesychius of Miletus, as the author himself avers. Other sources were the encyclopedia of Constantine VII Porphyrogenitus for the figures in ancient history, excerpts of John of Antioch for Roman history, the chronicle of Hamartolus for the Byzantine age. The biographies of Diogenes Laërtius, and the works of Athenaeus and Philostratus. Other principal sources include a lexicon by "Eudemus," perhaps derived from the work On Rhetorical Language by Eudemus of Argos.

Lost scholia

The lexicon copiously draws from scholia to the classics, and for later writers, Polybius, Josephus, the Chronicon Paschale, George Syncellus, George Hamartolus, and so on. The Suda quotes or paraphrases these sources at length. Since many of the originals are lost, The Suda serves an invaluable repository of literary history, and this preservation of the "literary history" is more vital than the lexicographical compilation itself, by some estimation.


The lexicon is arranged alphabetically with some slight deviations from common vowel order and place in the Greek alphabet according to a system called antistoichia ; namely the letters follow phonetically in order of sound, in the pronunciation of the tenth century which is similar to that of Modern Greek. The order is:
In addition, double letters are treated as single for the purposes of collation. The system is not difficult to learn and remember, but some editors—for example, Immanuel Bekker – rearranged the Suda alphabetically.


Little is known about the author, named "Suidas" in its prefatory note. He probably lived in the second half of the 10th century, because the death of emperor John I Tzimiskes and his succession by Basil II and Constantine VIII are mentioned in the entry under "Adam" which is appended with a brief chronology of the world. At any rate, the work must have appeared by before the 12th century, since it is frequently quoted from and alluded to by Eustathius who lived from about 1115 AD to about 1195 or 1196.
The work deals with biblical as well as pagan subjects, from which it is inferred that the writer was a Christian.
The standard printed edition was compiled by Danish classical scholar Ada Adler in the first half of the twentieth century. A modern translation, the Suda On Line, was completed on 21 July 2014.
The Suda has a near-contemporaneous Islamic parallel, the Kitab al-Fehrest of Ibn al-Nadim. Compare also the Latin Speculum Maius, authored in the 13th century by Vincent of Beauvais.