Which war did the Royal Marines participate in during the 18th century?

The Royal Marines participated in the American Revolutionary War, which took place between 1775 and 1783. During this conflict, the Royal Marines were deployed as an integral part of the British forces to help suppress the colonies' quest for independence from British rule. Their involvement included a variety of roles, from amphibious assaults to supporting naval operations, which highlighted their flexibility and tactical importance in various military engagements.

The American Revolutionary War marked a significant period for the Royal Marines, showcasing their capabilities in expeditionary warfare and establishing their prominence in subsequent military operations. Their history in this war helped shape the modern identity and operational role of the Royal Marines as a specialized fighting force within the British military.

The other conflicts listed occurred either before or after the 18th century. The War of the Roses was fought in the 15th century, World War I took place in the early 20th century, and while the Napoleonic Wars did occur in the early 19th century, they are outside the 18th-century timeframe being asked about in the question.