It is strange that there are very few mentions of Athenagoras' writings by other early Christian apologists, because he was well-known, and was also considered influential amongst both his peers and early Christians alike. He was respected for the powerful philosophical rhetoric used in his writing, which provided both a response to opponents of Christianity, and also a calming influence upon the more blusterous early Christians whose defense of their religion was not quite so tactful or as dignified as Athenagoras'. He is mentioned by Methodius about one hundred years after writing A Plea for the Christians, but nobody mentions him again until the fifth century.
Athenagoras was an Early Church Father, one of a group of influential Christian theologians and writers, who were scholars. They set the tenets of the early Christian church, although many were actually recent converts. Athenagoras, as his name suggests, came from Athens, a fact he was proud of and which he himself felt defined him.
The Plea is addressed to Roman emperor Marcus Aurelius and his son Lucius, who were co-emperors from A.D. 177-180. His defense of the Christian faith is eloquent but its leanings suggest that he was a Montanist; the Montanists were early Christians who were rather fundamentalist and strict; for example, Athenagoras calls the re-marriage of a widower as "cloaked adultery" which demonstrates the strictness of his beliefs. He also wrote frequently about ecstatic prophecy, which was a form of prophecy wholeheartedly embraced by the Montanist church.
Athenagoras passed away in the year 190 A.D. The Eastern Orthodox Church celebrates his feast day on July 24.