Seal and emblem of the United States Department of the Army

It displayed the designation "War Office", which was synonymous with Headquarters of the Army, and the Roman date MDCCLXXVIII (1778).

The changes were legislated by the National Security Act of 1947, and authorized by Section 3011, Title 10, United States Code.

The drum and drumsticks are symbols of public notification of the Army's purpose and intent to serve the Nation and its people.

The Phrygian cap (often called the "Cap of Liberty") supported on the point of an unsheathed sword and the motto "This We'll Defend" on a scroll held by the rattlesnake is a symbol depicted on some American colonial flags and signifies the Army's constant readiness to defend and preserve the United States.

[3] This "War Office Seal" is still used when legal certification is necessary to authenticate as "official" documents and records of the Department of the Army.

The Department of the Army Seal. It was formerly known as the "War Office Seal".
The Department of the Army Emblem
The seal of the U.S. Board of War and Ordnance .
"Military service mark" approved by the U.S. Department of Defense for usage by third parties to represent the U.S. Army in unofficial contexts. [ 1 ]