In the year 126, St Quadratus wrote an Apologia in defence of Christianity. Presented to the emperor Hadrian (117-138), the Apologia affected the persecution of Christians, since the emperor issued a decree saying that no one should be convicted without just cause. This Apologia was known to the historian Eusebius in the fourth century. At the present time, only part of this Apologia survives, quoted by Eusebius: "The deeds of our Savior were always witnessed, because they were true. His healings and raising people from the dead were visible not only when they were healed and raised, but always. They lived not only during the existence of the Savior upon the earth, but they also remained alive long after His departure. Some, indeed, have survived to our own time.
St Quadratus is also commemorated on January 4."
(taken from: http://ocafs.oca.org/FeastSaintsViewer.asp?FSID=102683)
HYMN OF PRAISE
The Holy Apostle Quadratus
(by St. Nikolai Velimerovich)
St. Quadratus, like the morning star,
The Epistle to Diognetos
"The Epistle of Mathetes to Diognetus is probably the earliest example of Christian apologetics, writings defending Christianity from its accusers. The Greek writer and recipient are not otherwise known, but the language and other textual evidence dates the work to the late 2nd century ; some assume an even earlier date and count it among the Apostolic Fathers." (http://en.wikipedia.org/wiki/Epistle_to_Diognetus)
"P. Andriessen has suggested that Quadratus' Apology is the work known as Epistle to Diognetus, a suggestion Michael W. Holmes finds "intreguing". While admitting that Epistle to Diognetus does not contain the only quotation known from Quadratus' address, Holmes defends this identification by noting "there is a gap between 7.6 and 7.7 into which it would fit very well." (http://en.wikipedia.org/wiki/Quadratus_of_Athens)
Regardless of whether or not the Apostle Quadratus is the author of this incredible document of early Christianity, it is worth reading, as it not only is one of the earliest Christian apologies, but also describes beautifully the life of the early Christians:
Kontakion in the Plagal of the Fourth Tone