From the architect of the capitol's web site:
https://www.aoc.gov/art/other-statues/statue-freedom
"He then sculpted a graceful figure in a classical dress wearing a liberty cap encircled with stars, holding a shield, wreath, and sword, which he said represented Armed Liberty. It was sent to Secretary of War Jefferson Davis, who was in charge of the overall construction at the Capitol. Davis objected to the liberty cap, the symbol of freed slaves, because "its history renders it inappropriate to a people who were born free and should not be enslaved." Davis suggested a helmet with a circle of stars. In response, Crawford designed a crested version of a Roman helmet, "the crest of which is composed of an eagle’s head and a bold arrangement of feathers, suggested by the costume of our Indian tribes." This third design was approved by Jefferson Davis in April 1856."