The fate of this otherwise obscure saint — he’s not to be confused with the first-century prelate to whom St. Paul addressed the shortest of his canonical epistles — is, of course, a byproduct of Christianity’s centuries-in-coming overthrow of the pagan world in which it incubated.
And in fact, Philemon the Actor’s martyrdom would have occurred towards the very end of the reign which saw the very last major anti-Christian persecutions. Already by this time, the young man whose sword arm would bear Christianity to its political triumph was a major political figure in the Empire.
The very next year, Constantine received the imperial purple, and over the ensuing years overcame his partners and rivals in that station to win unchallenged hegemony over the Roman World.
Laurels for Philemon and many others of his ilk would soon be policy for the empire that had put him to death, as celebration (perhaps exaggeration) of such travails cemented the newfound legitimacy of the formerly illicit religion elevated by Constantine.
Part of the Themed Set: The Church confronts its competition.