7. A certain time in which the Gospel was written is not able to be defined, with the accounts of Eusebius and Irenæus disagreeing.
Also, of the time in which he committed the Gospel to writing, I find the account sufficiently entangled.Eusebius, Church History, book II, chapters 15, 16, relying upon the testimonies of Papias and Clement, relates that Mark came to Rome with Peter, and there wrote his Gospel at the request of the Romans.But, that Peter came to Rome in the second year of Claudius Augustus, the same Eusebius writes in his Chronicon, with Baronius and Petavius agreeing, but with the Most Learned Valesius opposing, Annotationibus in Eusebium, page 33, where from the Acts of the Apostles he demonstrates that Peter remained in Judea and Syria until the last year of King Agrippa, which was the fourth year of Claudius.But the author of the Chronici Alexandrini indicates that Peter did not come to Rome before the seventh year of Claudius.Neither are there wanting those that call that Roman journey of Peter, and also his Roman Acts and contests, into question, moved especially by this reason, that Luke, who described lesser things at greater length, nowhere recorded it as a matter that was going to be of sufficiently great moment, if it were true.But Irenæus, in Eusebius’ Church History, book V, chapter 8, asserted that Mark wrote his Gospel μετὰτὴντούτωνἔξοδον, after the death of them (Paul and Peter).Which passage Christophorsonus rashly interpolated, and in the place of the common reading, which the consent of all the Codices, the authority of Ruffinus, and the ancient interpreters of Irenæus confirm, substituted this, μετὰδὲτούτουτὴνἔκδοσιν, after the publishing of this (that is, the Gospel of Matthew).Clearly he was afraid that this account would little agree with that Eusebius related above out of Papias and Clement.But would it be strange, thus the Most Learned Valesius knowingly argues in his Annotationibus, page 94, if in this matter the ancient Fathers differ among themselves, since concerning the writing of the holy Gospels we have almost nothing certain, except that there are only four, and that they were written by four authors.But at what time, and for what reason they were written, etc., there is little certainty.
 Claudius reigned as Roman Emperor from 41 to 54.  Denis Petau (1583-1652) was a French Jesuit churchman and scholar. His Opus de doctrina temporum carries on the chronological labors of Scaliger.  Ruffinus was a fourth century churchman, a friend of Jerome turned foe, a commentator, and a monastery builder. His work in the translation of Greek patristic literature into Latin has proven to be of great importance, preserving works that would have otherwise been lost.