Saints Perpetua and Felicity are amongst my favourites, showing as they did indomitable courage to defy family, convention and even the ties of their infant children (S Perpetua was still nursing her child; Felicity had her baby while imprisoned) in order to become and remain Christians in the year 203.
They are particularly fascinating because of the record S. Perpetua wrote of their imprisonment, the first surviving account of early Christianity by a woman, and it was widely read in the early Church. You can read it here (it isn't very long).
S. Perpetua was a well-to-do, well educated matron of 22. Felicity was a slave. Both decided to become Christians in defiance of a prohibition on conversion by the Emperor. Several attempts to dissuade them from their course failed, and in fact the group imprisoned grew in number as their catechist joined them in jail, and in fact they converted their jailer.
They were sentenced to the beasts in the arena. S. Perpetua had to guide the axe man's sword to her neck before she was finally beheaded.
Would that we all had such courage!