The most significant impact of the Bubonic Plague on medieval Europe was:
A decline in the power of the Catholic Church and rise of anti-Semitism.
The plague led to a significant loss of faith in the Church, as people struggled to understand why such a calamity was happening and many viewed the clergy's inability to provide help or answers as a failure. This also contributed to a rise in scapegoating, including increased anti-Semitism, as minority groups were often blamed for the spread of the disease.