The 66th Armor Regiment is the oldest armored unit in the United States Army, tracing its lineage to the 301st Battalion, Tank Corps, which served with distinction soon after it was formed in the First World War; the 301st trained at Camp Meade, Maryland, where then-Cpt. Dwight D. Eisenhower was an instructor. It has often been rumored that the 301st, the parent unit of the 66th, was first commanded by Col. George S. Patton, but this appears not to have been the case; while Patton was the first officer assigned to the Tank Corps, and while the 301st Tank Battalion was the first unit formed, Patton went nearly immediately to France to train Americans attached to Allied commands. The 301st was the only American heavy tank battalion to have seen action in the war. After the war, the 301st transitioned in the Regular Army to become the 66th Infantry Regiment by way of the 16th Tank Battalion.