In Greek mythology, Actaeus (/ækˈtiːəs/; Ancient Greek: Ἀκταῖος, lit. 'coast-man'^[1]), also called Actaeon,^[2] was the first king of Attica, according to Pausanias.^[3]

King Actaeus was the father of Aglaurus, the namesake of the daughter of King Cecrops who according to the Parian Chronicle changed the name of the kingdom of Acte, named after Actaeus, to the kingdom of Cecropia, later to be known as Attica. Scamon of Mytilene refers in his work 'Discoveries' that King Actaeus like King Cecrops according to the historically authoritative Parian Chronicle 1318 years later,^[4] had three daughters named Aglaurus, Erse and Pandrosos, who all got offspring, but also a fourth daughter, Phoenice, who died a virgin. The wife of King Actaeus, or who is the mothers of his daughters appears strangely obscure. His relation with the chaste, yet wild Artemis is curious.

According to the Byzantine Suda Lexicon, the ancient Greek historian Scamon of Mytilene claimed that Actaeus named the Phoenician letters in honor of his daughter Phoenice, who had died a virgin.^[5]

Actaeus was said to have ruled over the kingdom of Attica, named Acte (Ἀκτή Akte) or Actica^[2], before it became known as Cecropia more than a thousand years later.

The ancient Parian Chronicle inscribed in pure marble from Paros states that Actaeus gave Aktike^[6] its name before it was changed to Cecropia by King Cecrops, and thus later become known as Attica. Another story tells that Atthis, a daughter of Cranaos, the king succeeding Cecrops in Athens, was Attica's namesake. According to the Bibliotheca, on the other hand, Cecrops was the first king of Athens, and the three daughters were his own.^[7]

When King Aktaion saw Artemis bathing, she changed him into a stag. Afterwards his own hounds killed him.^[8] This marks the beginning of the first year of the marble Parian Chronicle, although with its first entry in the year 1318 after this event, when King Cecrops changes the name of Aktike to Cecropia. Year 1318 of Aktike confers to the Gregorian timeline's 1581 BC, according to the Digital Marmor Parium project at the University of Leipzig, directed by Dr. Monica Berti^[9]

Actaeus armatus, a Middle Cambrian (~505 MA) arthropod from the Burgess Shale, was named after Actaeus.^[10]

• Apollodorus, The Library with an English Translation by Sir James George Frazer, F.B.A., F.R.S. in 2 Volumes, Cambridge, MA, Harvard University Press; London, William Heinemann Ltd. 1921. ISBN 0-674-99135-4. Online version at the Perseus Digital Library. Greek text available from the same website.
• Hard, Robin, The Routledge Handbook of Greek Mythology: Based on H.J. Rose's "Handbook of Greek Mythology", Psychology Press, 2004. ISBN 978-0-415-18636-0. Google Books.
• Pausanias, Description of Greece with an English Translation by W.H.S. Jones, Litt.D., and H.A. Ormerod, M.A., in 4 Volumes. Cambridge, MA, Harvard University Press; London, William Heinemann Ltd. 1918. ISBN 0-674-99328-4. Online version at the Perseus Digital Library
• Pausanias, Graeciae Descriptio. 3 vols. Leipzig, Teubner. 1903. Greek text available at the Perseus Digital Library.
• Smith, William, Dictionary of Greek and Roman Biography and Mythology, London (1873). Online version at the Perseus Digital Library.
• Suida, Suda Encyclopedia translated by Ross Scaife, David Whitehead, William Hutton, Catharine Roth, Jennifer Benedict, Gregory Hays, Malcolm Heath Sean M. Redmond, Nicholas Fincher, Patrick Rourke, Elizabeth Vandiver, Raphael Finkel, Frederick Williams, Carl Widstrand, Robert Dyer, Joseph L. Rife, Oliver Phillips and many others. Online version at the Topos Text Project.

 This article incorporates text from a publication now in the public domain: Smith, William, ed. (1870). "Actaeus". Dictionary of Greek and Roman Biography and Mythology.