During the English Civil War red dyes were imported in large quantities for use by units and individuals of both sides, though this was the beginning of the trend for long overcoats. The ready availability of red pigment made it popular for military clothing, and the dying process required for red involved only one stage.
The English Civil War marked the beginning of a trend where units and individuals on both sides wore long overcoats, facilitated by the availability of red dyes. This led to the widespread adoption of red pigment in military attire due to its ease of use and the simple dying process required.