:Aelianus Tacticus, Greek military writer of the 2nd century CE, resident at Rome, is sometimes confused with Claudius Aelianus.

Claudius Aelianus (ca. 175–ca. 235), often seen as just Aelian, born at Praeneste, was a Roman author and teacher of rhetoric who flourished under Septimius Severus and probably outlived Elagabalus, who died in 222. He spoke Greek so perfectly that he was called "honey-tongued" (meliglossos); Roman-born, he preferred Greek authors, and wrote in a slightly archaizing Greek himself.

His two chief works are valuable for the numerous quotations from the works of earlier authors, which are otherwise lost, and for the surprising lore, which offers unexpected glimpses into the Greco-Roman world-view.

On the Nature of Animals, ("On the Characteristics of Animals" is an alternative title; usually cited, though, by its Latin title), is a curious collection, in 17 books, of brief stories of natural history, sometimes selected with an eye to conveying allegorical moral lessons, sometimes because they are just so astonishing: :"The Beaver is an amphibious creature: by day it lives hidden in rivers, but at night it roams the land, feeding itself with anything that it can find. Now it understands the reason why hunters come after it with such eagerness and impetuosity, and it puts down its head and with its teeth cuts off its testicles and throws them in their path, as a prudent man who, falling into the hands of robbers, sacrifices all that he is carrying, to save his life, and forfeits his possessions by way of ransom. If however it has already saved its life by self-castration and is again pursued, then it stands up and reveals that it offers no ground for their eager pursuit, and releases the hunters from all further exertions, for they esteem its flesh less. Often however Beavers with testicles intact, after escaping as far away as possible, have drawn in the coveted part, and with great skill and ingenuity tricked their pursuers, pretending that they no longer possessed what they were keeping in concealment."

The Loeb Classical Library introduction characterizes the book as :"an appealing collection of facts and fables about the animal kingdom that invites the reader to ponder contrasts between human and animal behavior."

Aelian's anecdotes on animals rarely depend on direct observation: they are almost entirely taken from written sources, often Pliny the Elder, but also other authors and works now lost, to whom he is thus a valuable witness. He is more attentive to marine life than might be expected, though, and this seems to reflect first-hand personal interest; he often quotes "fishermen". At times he strikes the modern reader as thoroughly credulous, but at others he specifically states that he is merely reporting what is told by others, and even that he does not believe them. Aelian's work is one of the sources of medieval natural history and of the bestiaries of the Middle Ages; in some ways an allegory of the moral world, an Emblem Book.

Conrad Gessner (or Gesner), the Swiss scientist and natural historian of the Renaissance, made a Latin translation of Aelian's work, to give it a wider European audience. The latest Latin translation is that of Friderich Jacobs (1832), based on both Gesner's translation and that of Petrus Gillius (1533). An English translation by A. F. Scholfield has been published in the Loeb Classical Library.

Various History — for the most part preserved only in an abridged form — is Aelian's other well-known work, a miscellany of anecdotes and biographical sketches, lists, pithy maxims, and descriptions of natural wonders and strange local customs, in 14 books, with many surprises for the cultural historian and the mythographer, anecdotes about the famous Greek philosophers, poets, historians, and playwrights; myths instructively retold. The emphasis is on various moralizing tales about heroes and rulers, athletes and wise men; reports about food and drink, different styles in dress or lovers, local habits in giving gifts or entertainments, or in religious beliefs and death customs; and comments on Greek painting. Aelian gives an account of fly fishing, using lures of red wool and feathers, of lacquerwork, serpent worship — Essentially the Various History is a Classical "magazine" in the original senses of that word. He is not perfectly trustworthy in details, and his agenda is always to inculcate culturally "correct" Stoic opinions, perhaps so that his readers will not feel guilty, but Jane Ellen Harrison found survivals of archaic rites mentioned by Aelian very illuminating in her Prolegomena to the Study of Greek Religion (1903).

Two English translations of the Various History, by Fleming (1576) and Stanley (1665) made Aelian's miscellany available to English readers; a recent English translation of Aelian's Varia Historia is by Diane Ostrom Johnson, 1997.

Considerable fragments of two other works, On Providence and Divine Manifestations, are preserved in the early medieval encyclopedia, the Suda. Twenty "letters from a farmer" after the manner of Alciphron are also attributed to him. The letters are invented compositions to a fictitious correspondent, which are a device for vignettes of agricultural and rural life, set in Attica, though mellifluous Aelian once boasted that he had never been outside Italy, never been aboard a ship (which is at variance, though, with his own statement, de Nat. An. XI.40, that he had seen the bull Serapis with his own eyes). Thus conclusions about actual agriculture in the Letters are as likely to evoke Latium as Attica. The fragments have been edited in 1998 by D. Domingo-Foraste, but are not available in English. The Letters are available in the Loeb Classical Library series.

*De natura animalium at LacusCurtius (complete Latin translation) *Some quotes from Aelian's natural history (English) *Aelian from the fly-fisherman's point-of-view

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