Within countries and kingdoms, kings and Popes often clashed.
How dare the Pope question my authority?!
They often argued about who should have the right to choose religious officials; the king wanting to choose, but the Pope saying it's up to them.
Alright, just hurry and leave, you've been standing there for three days
Please... I beg forgiveness
Emperor Henry IV had chosen a new bishop, but that displeased Pope Gregory VII, who came into power in 1073.
Emperor Henry accused the Pope of questioning his authority and eventually, was excommunicated by said Pope.
Trying to beg for forgiveness afterwards, Henry IV stood outside of the castle where the Pope was staying, barefoot for three days until he was forgiven.
Even afterwards, a settlement had not been made and kings and popes still continued to clash for power, but ultimately agreeing that Popes chose bishops and abbots, but they still had to live under the emperor.