The Great Seal of the United States
The Great Seal was first used on the reverse of the $1 Silver Certificate in 1935. The Department of State is official keeper of the Seal. Symbolically, the seal reflects the beliefs and values that the Founding Fathers attached to the new nation and wished to pass on to their descendants. Charles Thompson (Secretary of Congress - 1782) explained the obverse side of the seal this way: The red and white stripes of the shield "represent the several states...supporting a [blue] Chief which unites the whole and represents Congress." The colors are adopted from the American flag: "White signifies purity and innocence, Red, hardiness & valor, and Blue, the colour of the Chief, signifies vigilance, perseverance & justice." The shield, or 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."
The number 13, denoting the 13 original States, is represented in the bundle of arrows, the stripes of the shield, and the stars of the constellation. The olive branch and the arrows "denote the power of peace and war." The constellation of stars symbolizes a new nation taking its place among other sovereign states. The motto E Pluribus Unum, emblazoned across the scroll and clenched in the eagle's beak, expresses the union of the 13 States. Recent scholarship has pointed out the probable source of this motto: Gentleman's Magazine, published in London from 1732 to 1922, was widely read by the educated in the American Colonies. Its title page carried that same motto and it is quite possible that it influenced the creators of the seal.
The reverse, sometimes referred to as the spiritual side of the seal, contains the 13-step pyramid with the year 1776 in Roman numerals on the base. At the summit of the pyramid is the Eye of Providence in a triangle surrounded by a Glory (rays of light) and above it appears the motto Annuit Coeptis, or "He (God) has favored our undertakings." Along the lower circumference of the design appear the words Novus Ordo Seclorum, or "A new order of the ages," heralding the beginning of the new American era in 1776.
If you are interested in a more detailed history of the Great Seal of the United States, you should contact the U.S. Department of State directly.