Pro-martyr

Such a man was John Brown. He was strong in his moral and mental nature, as well as in his physical nature. He was born to lead; and he led, and made himself the pro-martyr of a cause rapidly perfecting.

Source: wiktionary

John was a son, probably the younger son, of Zebedee and Salome and a brother of the elder James who became the pro-martyr of the apostles.

Source: wiktionary

We have a tragic instance of baneful clericalism in the death of Patrick Hamilton, the pro-martyr of the Scottish Reformation

Source: wiktionary

Among the scholars at Douai, men were being prepared to serve as priests and some showed themselves eager to cross over to England immediately rather than wait upon events. Cuthbert Mayne was captured and executed in 1577 and is regarded as the pro-martyr of the seminary priests.

Source: wiktionary