What the above writeups fail to mention is that there was in fact a real man named Phaedrus, back many milennia. He wrote fables; five volumes of them, in fact. All in Latin.
Phaedrus was (as far as we know) born in Macedonia c. 14 AD. He was a slave, and was then freed by the Roman emperor Augustus. It is not known when he died.
Phaedrus's fables were partly translations/summarizations of the fables of Aesop and partly taken from the folklore of the time (he was not considered a good writer). They overwhelmingly tend to deal with animals and rural environments. They are extremely short; 40 words or less is about average. They are written in iambic meter. One of them (Pastor et capella), to give an example, deals with a farmer who breaks his sheep's horn and is then found out and punished by his master (moral: keep quiet and you'll get your due). The morals are always present and are always simple and to-the-point. Only 93 fables survive.
Ironically, the man who himself plagiarized and generally did unoriginal things was himself much copied and imitated later. A number of the stories that circulated in Europe under Aesop's name could be in fact traced back to Phaedrus. La Fontaine, the great French fabulist, was an imitator(though a much superior one) of his.
Information: http://19.1911encyclopedia.org/P/PH/PHAEDRUS.htm (wonder if she's related to Webster 1913). A complete collection of his works (in Latin) can be found at: http://www.thelatinlibrary.com/phaedr.html.