Roughly the dividing line between use of oil vs. butter (or lard) in traditional regional cuisine was slightly north of Bologna, until relatively recent times (I would say until post 2nd world war).

South, oil.

North, butter.

My grandmother (from Parma) firmly believed that olive oil was to be used uncooked for salads and similar.

JFYI:

https://www.cittadellolio.it/2017/06/15/olio-cucina-4-secoli...