It is believed that it is then that the term Dutch courage was coined. Either because the English soldiers drank before a battle to fight the fear with Dutch gin, or because they saw the Dutch soldiers drink jenever and witnessed the bravery with which they fought after it.

What is the meaning of the idiom Dutch courage?

Dutch courage, also known as pot-valiance (or potvaliancy) or liquid courage, refers to courage gained from intoxication with alcohol.