On June 20, 1782, the United States Congress adopted the Great Seal of the United States after six long years of debate and discussion.
The front of the seal depicts a bald eagle clutching an olive branch in its right talon and arrows in its left. On its breast appears a shield marked with 13 vertical red and white stripes topped by a bar of blue.
The eagle’s beak clutches a banner inscribed, E pluribus unum, a Latin phrase meaning “Out of Many One.” Above the eagle’s head, golden rays burst forth, encircling 13 stars.
The only official explanation of the symbolism of the great seal was given by Charles Thomson upon presenting the final design to Congress.
The Escutcheon is composed of the chief & pale, the two most honorable ordinaries. The Pieces, paly, represent the several states all joined in one solid compact entire, supporting a Chief, which unites the whole & represents Congress. The Motto alludes to this union. The pales in the arms are kept closely united by the chief and the Chief depends upon that union & the strength resulting from it for its support, to denote the Confederacy of the United States of America & the preservation of their union through Congress.
The colours of the pales are those used in the flag of the United States of America; White signifies purity and innocence, Red, hardiness & valor, and Blue, the colour of the Chief signifies vigilance, perseverance & justice. The Olive branch and arrows denote the power of peace & war which is exclusively vested in Congress. The Constellation denotes a new State taking its place and rank among other sovereign powers. The Escutcheon is born on the breast of an American Eagle without any other supporters to denote that the United States of America ought to rely on their own Virtue.
Reverse. The pyramid signifies Strength and Duration: The Eye over it & the Motto allude to the many signal interpositions of providence in favour of the American cause. The date underneath is that of the Declaration of Independence and the words under it signify the beginning of the new American Era, which commences from that date.
Thomson took the symbolism for the colors from a book called Elements of Heraldy by Antoine Pyron du Martre, which William Barton had lent to him. That book claimed that argent (white) “signifies Purity, Innocence, Beauty, and Genteelness“, gules (red) “denotes martial Prowess, Boldness, and Hardiness“, and azure (blue) “signifies Justice, Perseverance, and Vigilance“.
Several of the earlier drafts of the seal are shown below.