Who were the redcoats in seventeenth century?

The term "Redcoats" wasn't really used in the 17th century. It was a nickname that came about later, specifically in the 18th century, to refer to British soldiers due to the distinctive red coats they wore.

In the 17th century, British soldiers were simply known as:

* The British Army: This was the official name.

* The English Army: This was often used before the Acts of Union in 1707 that officially established the Kingdom of Great Britain.

* King's (or Queen's) Troops: This referred to the soldiers directly under the command of the monarch.

While red coats were a part of military uniforms in the 17th century, they weren't the defining color. Other colors like blue and yellow were also common, and the red coats weren't as ubiquitous as they became in the 18th century.

So, in summary: While the "Redcoats" were a prominent feature of British military appearance by the 18th century, the term wasn't in use during the 17th century.