hi! there's room for more information here, but there have been a few discussions that may be of interest:

• Most Germanic countries are predominantly Protestant/Reformed while Latin countries are predominantly Catholic. Why did this split happen?

• Why did Southern Germany stay Catholic after the Protestant Reformation?

• How did Scandinavian countries become Protestant while much of Europe remained Catholic - includes a handy map in the post header

• How did Poland remain Catholic?

• Why did the Protestant/Reform movement never take hold in Spain or Italy?

• How did Ireland manage to stay mostly Catholic?

• Protestantism among the Irish: Who joined the Church of Ireland? (not as relevant to your question, just an interesting tangentially-related post)