Hermenegild, though an Arian, married a Catholic and became a convert. His father on hearing the news had him imprisoned. On Easter Day an Arian priest entered his cell and offered him pardon if he would receive communion from him. Hermenegild refused and knelt with joy for the death stroke.
Then shall the just stand with great constancy against those that have afflicted them and taken away their labors. — Epistle, Book of Wisdom
The Imitation of Christ
Oh, how many and grievous tribulations did the Apostles suffer, and the martyrs, and confessors, and virgins, and all the rest who resolved to follow the steps of Christ.
The son of a heretical father, Hermenegild became a Christian and was in consequence put to death upon the order of his own father, for whom the martyr prayed even when dying. His prayer converted his father, who strove to do what he could to bring his kingdom back to the true Faith.
The prayer of the dying St. Stephen gave to the world the glorious St. Paul; the prayer of Hermenegild was instrumental in bringing a kingdom to the Faith. Pray for the conversion of sinners, even if you never know the definite persons who have been converted by your prayers; you will meet them in heaven.
He that shall convert one sinner from his evil ways, shall save his own soul from death.