Before mass communication became possible, no sane person would leave home to join an army, so kings and tyrants and such scumbags would empty the prisons, insane asylums etc. and use these for soldiers, giving them a flashy uniform.
Soldiers were always avoided by all, especially children.
Mass communication was invented in Prussia ~1815; it is called "school".
Prussia used the resultant masses of dumbed-down dummies to defeat the French in the Franco-Prussian war; while the French had the first ever quick-firing cannon which slaughtered the Prussians by the thousands, the Prussians had many more thousands who had been made so stupid that they marched right at the cannons.
So now you know why we are all forced to go to school, and why soldiers have "dress uniforms".