The state seal of Colorado is a modification of the Territorial Seal of Colorado, which was adopted by the First Territorial Assembly on 6 November 1861. The state seal substituted the title “State of Colorado” for the territorial name and the new date of “1876” for that of 6 November 1861. Otherwise, the state seal remains in its details and symbols the same as the former Territorial Seal of Colorado. The date imprinted on the state seal is 1876, the year Colorado joined the Union. The seal was not approved by the Colorado legislature until 15 March 1877.
Lewis Leyward Weld, the Territorial Secretary appointed by President Abraham Lincoln in 1861, was primarily responsible for the design of the territorial seal which became the basis of the state seal of Colorado. It is also believed that Governor William Gilpin also had a role in the creation of the Territorial Seal of Colorado, as the design contains symbols from the family coat-of-arms of each man. Both men were also know to have studied the art and symbolism of medieval heraldry which play a part in the seal’s design.
In the outer circle of the seal, the top half contains the legend “State of Colorado.” The bottom half is inscribed with the date 1876, the year of Colorado’s admission to the Union. The date is flanked by three blue stars on each side, which round out the circle.
At the top of the circular seal is the eye of God inside a triangle. It symbolizes the presence of God, who sees all, in all things. Golden rays shoot from around the eye in an arc. Beneath the triangle are Roman fasces, which are made of a bundle of elm and birch rods and a battle axe tied together by thongs. A Roman fasces is the emblem of a republican form of government.
On the state seal of Colorado, the rods are bound to the axe with thongs of red, white, and blue, signifying the colors of the American flag. The rods bound together signify the power of the state in its unity with the other states. The axe is a symbol of strength, leadership and authority. On the bands of the thongs a scroll is inscribed with the phrase “Union and Constitution.”
Beneath the scroll is a shield which displays on its top half three snow covered mountains on a red background. Colorado is a mountainous state, home to the immense Rocky Mountains. A crossed pick and axe on a gold background, insignias of Colorado’s important mining trade, are shown on the bottom half of the shield. In a semi-circle beneath the shield on the state seal of Colorado is the state's motto, "Nil Sine Numine," a Latin phrase which translates to “nothing without the Deity.”