Forty winks. The back forty. Forty acres and a mule. Ali Baba and the Forty Thieves. It is just one of those numbers. It isn't quite as good as three, seven, or twelve, but forty still seems to be a magic number. So powerful in fact that a last minute substitution was all that prevented this whole martyrdom from being consigned to the dustbin. Truth: Thirty-nine Steps was spooky, but 39 martyrs just wouldn't work.
The reign of Licinius was a good time to persecute Christians. Okay, it was the Roman Empire, so every day was a good day to persecute Christians, even after Christianity became the official religion, except that the Christians persecuted then were heterodox, or as they're more commonly called, heretics. But that's another day. March 10 is for victims of the polytheists who demanded incense offered to Jupiter and the numen of the Emperor.
There was a military unit in Armenia called the Fulminata Legion, translated variously as the Thunderstruck Legion or the Legion Armed with Lightning. The latter name means something cooler, but the former name has better flow. Either way, there were forty Christians within this legion who would not give up their faith.
The plan for their execution was simple. Strip them naked and leave them exposed on a frozen lake. Set up hot baths on the shore for any who will sacrifice to the gods. These Fulminati (-ae? -a?) decided not to abandon each other and their faith, so they huddled the whole night, slowly losing body heat. At some point, one of them caved and ran to the baths. A guard, noting the epiphanos around the martyrs, stripped naked, declared himself a Christian, and joined them, thus preserving the round, magic total of forty.
In the morning, their stiffened (though not quite dead) bodies were heaped in a pyre and reduced to ashed.
At first, the thing that attracted me to this was the low cast, simple means of execution. However, as I began writing it, the importance of forty became clearer to me.