Lineage and Honors: The certificates attesting to a unit's lineage and honors are probably the most important documents relating to the history of the unit. Issued by the Army's Center of Military History, they are the unit's birth certificate, deed to organizational properties, and its service record.

Constituted 2 March 1833 in the Regular Army as the United States Regiment of Dragoons.

Organized 4 March 1833 at Jefferson Barracks, Missouri.

Redesignated 15 May 1836 as the First Regiment of Dragoons.

Redesignated 3 August 1861 as the First Cavalry.

Assigned in December 1917 to the 15th Cavalry Division

Relieved in May 1918 from assignment to the 15th Cavalry Division.

Assigned 20 August 1921 to the 1st Cavalry Division.

Relieved 3 January 1933 from assignment to the 1st Cavalry Division.

Reorganized and redesignated 16 January 1933 as the 1st Cavalry, Mechanized.

Redesignated 15 July 1940 as the 1st Armored Regiment, Light and assigned to the 1st Armored Division.

Regiment broken-up 20 July 1944 and its elements reorganized and redesignated as follows:

Regiment (less 2nd Battalion) as the 1st Tank Battalion and remained assigned to the 1st Armored Division.

2nd Battalion disbanded.

After 20 July 1944 the above elements underwent changes as follows:

1st Tank Battalion converted and redesignated 1 May 1946 as the 1st Constabulary Squadron; concurrently relieved from assignment to the 1st Armored Division and assigned to the 15th Constabulary Regiment.

Inactivated 20 December 1948 in Germany; concurrently relieved from assignment to the 15th Constabulary Regiment, converted and redesignated as the 1st Medium Tank Battalion, and assigned to the 1st Armored Division.

Activated 7 March 1951 at Fort Hood, Texas.

Redesignated 20 May 1953 as the First Tank Battalion.

2d Battalion, 1st Armored Regiment, reconstituted 27 February 1951 in the Regular Army; concurrently redesignated as the 100th Tank Battalion and assigned to the 1st Armored Division.

Activated 7 March 1951 at Fort Hood, Texas.

1st and 100th Tank Battalions relieved 15 February 1957 from assignment to the 1st Armored Division; concurrently consolidated, reorganized, as redesignated as the 1st Cavalry, a parent organization under the Combat Arms Regimental System.

Withdrawn 16 May 1989 from the Combat Arms Regimental System and reorganized under the United States Regimental System with Headquarters at Fort Hood.