Uniforms originally served a purpose similar to battle flags or ensigns. They served to identify individual members while the flags identified units as a whole. Some uniforms originally consisted of nothing more than brightly colored scarves tied around an arm or waist, and this tradition continues in many irregular wars today. Anything that can set individuals in one group apart from individuals in another can count as a uniform
As uniforms came to be an entire suit of clothing, the bright, or at least varied, colors remained. Everyone knows that the 'Redcoats' are British, and that French and most Prussian troops wore blue. Everyone is only partially correct.
The differences in uniforms within one country's military is influenced by any number of things. When standing armies began to be the norm, the regiment became the primary organizational unit. Forming a regiment was often a semi informal affair, with the Colonel not only recruiting his troops, but also paying and clothing them. In the absence of strict uniform regulations, the Colonel frequently designed his own and this resulted in each regiment having their own distinctive, often gaudy, uniforms. By the time uniform regulations began to be written, many of these uniforms were 'grand fathered in' and accepted as the traditional uniform for that regiment. Traces of these uniforms remain in the formal dress uniforms worn today. Http://www.regiments.org/milhist/america... contains links that include pictures showing the wide variety of uniforms used by the British Army beginning in the 1700s. http://uniform-evolution.napoleonicwars.... has a good beginning for most other European nations.
Regimental organizations eventually gave way to national armies. The regiments maintained their identities, and their uniforms; and this resulted in confusion while in the field, (too many opposing units were wearing similar uniforms) and the need to standardize somewhat. Change came slowly. By the time of the War to Rid the Empire of the Colonies, the majority of the British Army wore red uniform jackets, but many cavalry or specialty units wore blue or green. Different colors were used for the facings, or lining. The mercenary Hessian troops wore their own uniforms. So confusion continued, but was becoming less common.
