Pope Eugene IV, Council of Florence, 1441, ex cathedra:
“The… Church firmly believes, professes and preaches that all those who are outside the Catholic Church, not only pagans but also Jews or heretics and schismatics, cannot share in eternal life and will go into the everlasting fire which was prepared for the Devil and his angels, unless they are joined to the Church before the end of their lives; that the unity of this ecclesiastical body is of such importance that only for those who abide in it do the Church’s sacraments contribute to salvation and do fasts, almsgiving and other works of piety and practices of the Christian militia produce eternal rewards; and that nobody can be saved, no matter how much he has given away in alms and even if he has shed blood in the name of Christ, unless he has persevered in the bosom and unity of the Catholic Church.
Pope Eugene IV's qualification "even if he has shed blood in the name of Christ" seems to imply that to shed blood in the name of Christ is a work of piety of such value that some parishioners might expect should allow a person to be saved.
This might be confusing to the modern reader, since in modern English, the idiom "to shed blood" usually means to kill another, especially in an act of violence. The non-Catholic might read this as a commendation of those participating in violent acts associated with the Catholic church like the crusades or the execution of heretics.
What does it mean to "shed blood in the name of Christ"?
Do any other Catholic documents use these words to describe an act of piety?