From 15th Century
The Feast was universally celebrated; and Christian piety
introduced an oath to defend the belief in the Immaculate
Conception to be taken not only by Religious, but also by
non-Religious and at the Universities (e.g., Paris, 1497;
Cologne, 1499; Vienna, 1501).
From the 17th Century
The clause "to the shedding of blood" was added to the oath
taken to defend the belief in the Immaculate Conception.