title: Advanced Base Force
context: The United States Marine Corps's Advanced Base Force (Advance Base Force in some references) was a coastal and naval base defense force that was designed to set up mobile and fixed bases in the event of major landing operations within, and beyond, the territorial United States.[1] Established in the beginning of the 20th century, the Advanced Base Force was the United States' first combined task force built on the concept of the Marine Corps' traditional role in expeditionary warfare. The slow development of the advanced base force played a significant role in the controversy over the removal of the ships' guards (Marines on Navy ships) in 1908–1909.[2]
question: When was the Marines Advanced Base Force formed?
answers: in the beginning of the 20th century