10. When did the first major involvement of American troops in Vietnam begin? What were these troops called?

The first major involvement of American troops in Vietnam began in March 1965. These troops were called the United States Army of the Republic of Vietnam (USARV). The USARV was a ground force of the Army of the Republic of Vietnam (ARVN), which was the ground forces of the South Vietnamese military. The USARV was established in 1956 and was composed of South Vietnamese soldiers trained by the United States. The USARV was responsible for conducting ground operations against the North Vietnamese and the Viet Cong during the Vietnam War.