John Tzetzes (Greek : Ἰωάννης Τζέτζης, translit. Iōánnēs Tzétzēs; c. 1110, Constantinople – 1180, Constantinople) was a Byzantine poet and grammarian who is known to have lived at Constantinople in the 12th century.
He was able to preserve much valuable information from ancient Greek literature and scholarship. 
Tzetzes described himself as pure Greek on his father's side and part Iberian (Georgian) on his mother's side.  In his works, Tzetzes states that his grandmother was a relative of the Georgian Bagratid princess Maria of Alania who came to Constantinople with her and later became the second wife of the sebastos Constantine Keroularios, megas droungarios and nephew of the patriarch Michael Keroularios. 
He worked as a secretary to a provincial governor for a time and later began to earn a living by teaching and writing.  He was described as vain, seems to have resented any attempt at rivalry, and violently attacked his fellow grammarians. Owing to a lack of written material, he was obliged to trust to his memory; therefore caution has to be exercised in reading his work. However, he was learned, and made a great contribution to the furtherance of the study of ancient Greek literature.
Tzetzes published a collection of 107 of his Letters addressed partly to fictitious/unidentified personages, and partly to influential men and women of the writer's time. They contain a considerable amount of social and biographical information, and are full of learned allusions to history, rhetoric, and mythology.
These letters became the springboard for what became during the Renaissance perhaps the most influential of his many works, the Book of Histories, usually called Chiliades ("thousands") from the arbitrary division by its first editor (N. Gerbel, 1546) into books each containing 1,000 lines. The work consists of 12,674 lines of political verse, divided into 660 topics, each of which is a gloss on a literary, historical, or other learned reference in one of his published letters. The first 141 histories serve as poetic footnotes to a verse letter Tzetzes addressed to John Lachanas, an official in Constantinople. 
This collection of literary, historical, theological, and antiquarian miscellanies provides an important snapshot of the intellectual world of Constantinople in the mid-12th century, and also preserves fragments of more than 200 ancient authors, including many whose works have been lost.  The author subsequently brought out a revised edition with marginal notes in prose and verse (ed. T. Kiessling, 1826; on the sources see C. Harder, De J. T. historiarum fontibus quaestiones selectae, diss., Kiel, 1886). 
Tzetzes supplemented Homer's Iliad by a work that begins with the birth of Paris and continues the tale to the Achaeans' return home.
The Homeric Allegories, in "political" verse and dedicated initially to the German-born empress Irene and then to Constantine Cotertzes,  are two didactic poems, the first based on the Iliad and the second based on the Odyssey, in which Homer and the Homeric theology are set forth and then explained by means of three kinds of allegory: euhemeristic (πρακτική), anagogic (ψυχική) and physic (στοιχειακή). These works were translated into English in 2015 and 2019 by Adam J. Goldwyn and Dimitra Kokkini.  
In the Antehomerica, Tzetzes recalls the events taking place before Homer's Iliad. This work was followed by the Homerica, covering the events of the Iliad, and the Posthomerica, reporting the events taking place between the Iliad and the Odyssey. All three are currently available in English translations.
Tzetzes also wrote commentaries on a number of Greek authors, the most important of which is that elucidating the obscure Cassandra or Alexandra of the Hellenistic poet Lycophron, usually called "On Lycophron" (edited by K.O. Müller, 1811), in the production of which his brother Isaac is generally associated with him. Mention may also be made of a dramatic sketch in iambic verse, in which the caprices of fortune and the wretched lot of the learned are described; and of an iambic poem on the death of the emperor Manuel I Komnenos, noticeable for introducing at the beginning of each line the last word of the line preceding it (both in Pietro Matranga, Anecdota Graeca 1850).
For the other works of Tzetzes see J. A. Fabricius, Bibliotheca graeca (ed. Harles), xi.228, and Karl Krumbacher, Geschichte der byz. Litt. (2nd ed., 1897); monograph by G. Hart, "De Tzetzarum nomine, vitis, scriptis," in Jahn's Jahrbucher für classische Philologie. Supplementband xii (Leipzig, 1881). 
In Greek mythology and history, there were at least eleven men named Medon.
The name Astyoche or Astyocheia was attributed to the following individuals in Greek mythology:
Laodamas refers to five different people in Greek mythology.
Periphas in Greek mythology may refer to:
The name Eurymachus is attributed to the following individuals:
In Greek mythology, Helicaon or Helikaon was a Trojan warrior and son of the elder Antenor and the priestess Theano. He was the brother of Crino, including Acamas, Agenor, Antheus, Archelochus, Coön, Demoleon, Eurymachus, Glaucus, Iphidamas, Laodamas, Laodocus, Medon, Polybus, and Thersilochus.
In Greek mythology, Archelochus was a son of Antenor and Theano. Along with his brother, Acamas, and Aeneas, he shared the command of the Dardanians fighting on the side of the Trojans.
In Greek mythology, Agenor was a Trojan hero.
In Greek mythology, Acamas or Akamas, was the son of Trojan elder Antenor and Theano, was a participant in the Trojan War, and fought on the side of the Trojans.
In Greek mythology, Demoleon was a Trojan warrior, son of Antenor and Theano. His father was a counselor to King Priam and his mother was a priestess of Athena.
In Greek mythology, Polybus or Polybius was the son of Antenor and Theano. He was the brother of Crino, Acamas, Agenor, Antheus, Archelochus, Coön, Demoleon, Eurymachus, Glaucus, Helicaon, Iphidamas, Laodamas, Laodocus, Medon and Thersilochus.
In Greek mythology, the name Euchenor may refer to:
In Greek mythology, the name Iphidamas may refer to:
In Greek mythology, the name Polymela or Polymele may refer to the following figures:
In Greek mythology, the name Crino may refer to:
In Greek mythology, Coön, also known as Cynon (Κύνων), was the eldest son of Antenor and Theano. Like most of his brothers, he fought and fell in the Trojan War.
In Greek mythology, the female name Polymede may refer to:
Lysidice or Lysidike is the name of several women in Greek mythology.
In Greek mythology, Thersilochus may refer to three different figures:
Agenor was the name of the following Greek mythological characters:
In the twelfth century, John Tzetzes writes to a member of the imperial family: "I descend from the most noble of Iberians in my mother's family; from my father I am a pure Greek."