As I look at the posts I've made thus far, I realize they've been almost completely historical and linguistic. That's fine, but I don't want to lose sight of the fact that these inscriptions, which are overwhemlingly taken from the catacombs and cemetaries of Rome before Constantine, testify to the faith of people who expereinced something that, God willing, we never will: imprisonment, torture, and death for acknowledging our faith.  They had no idea how long the persecutions would last - they might have gone on forever - but these our ancestors kept their families in the Faith, and besides the Church and our Traditions, these monuments and inscriptions are tangible evidence of that.

And to add one linguistic note, the word 'marytr' comes from a Greek word which means 'to testify to'; 'to bear witness to'.  It's an ordinary legal term which was appropriated to dignify what the Martyrs were doing with their very lives.