Salve!
I live in northern Italy,in a region(Aemilia),where there was a strong gallic presence(the Boi tribe).During the centuries,there was a strong commistion between gallic and roman cultures,and some roman gods were given attributes of gallic origin.
In fact Jupiter was often called "Jupiter Taranis",as Taranis is the thunder god of the continental celts,and Mercury was identified with Lugos(Lugh),as the god of commerce and intellect.
Do you know other associations of such kind?
In my province in particular,Taranis was worshipped.