Aelius Herodianus () or Herodian (fl. 2nd century CE) was one of the most celebrated grammarians of Greco-Roman antiquity. He is usually known as Herodian except when there is a danger of confusion with the historian also named Herodian. Herodian was the son of Apollonius Dyscolus and was born in Alexandria. From there he seems to have moved to Rome, where he gained the favour of the emperor Marcus Aurelius, to whom he dedicated a work on prosody. Works Herodian was held in very high esteem by subsequent grammarians; Priscian describes him as maximus auctor artis grammaticae ("the greatest creator of grammatical art"). He wrote many works, but they are mostly fragmentary and it is very difficult to compile an accurate list of them. In numerous instances it is impossible to tell whether the titles given by writers who quote from his works are distinct treatises, or only portions of larger works. In addition, there are ongoing debates over which works were written by him and which were not. Some works by lesser-known figures are known to have been reattributed to Herodian, presumably in order to increase the prestige of the works. In total some fifty titles are known in connection with Herodian's name. The main works attached to his name (both rightly and wrongly) are as follows (the most usual way of citing each title is highlighted in bold): On peculiar style (). Probably the only complete work of Herodian's to have survived. Categories (, Partitiones). Devoted to explanations of difficult words found in Homer; many important quotations from the Partitiones are found in the scholia on Homer. General prosody (, or , or ; De prosodia catholica), in twenty books. Herodian dedicated this work to Marcus Aurelius. It covered prosody and etymology. Two epitomes and an index survive. It is possible that several other titles known to us were in fact parts of the Prosody: namely the Homeric prosody (); Attic prosody (); and Anomalous prosody (). A work entitled On accents (), attributed to Arcadius of Antioch but compiled by a later grammarian, Theodosius of Byzantium, seems to be an extract from Herodian's Prosody. On figures (, De figuris). This work is known to be spurious, i.e. it is transmitted under Herodian's name but was not written by him. The author is referred to as "pseudo-Herodian". Philetaerus (). This work is also known to be spurious; it