Since George Washington's days the US Military has had a symbol of rank. They have changed over the years but not by much. But they have changed, For example Major rank of WWI is 1/16 of an inch smaller than today's. Many of the ranks were not made of metal over this time period. Here are some examples of the ranks from the Colonel of 1840 to WWI. Including the I believe to be the most beautiful ranks insignia of all time. Spanish American War Colonel rank.