US Army, Pacific (USARPAC) traces its history back to 1898, when the United States first became a Pacific power and American soldiers first arrived in Hawaii. Hawaii soon became a power-projection platform for military operations in the Asia-Pacific region. Fort Shafter was built in 1905-07 and in 1921 became the headquarters for the Hawaiian Department. When Army and Navy forces in Hawaii and the Philippines came under attack on December 7, 1941, Hawaii quickly became a strategic hub. The Hawaiian Department became the Army component command under the Commander-in-Chief, Pacific Ocean Areas. As the campaigns progressed, the command was designated US Army Forces, Central Pacific Area (1943-44); US Army Forces, Pacific Ocean Areas (1944-45); and US Army Forces, Middle Pacific (1945-47). Its insignia, designed in 1944, depicted the axis of advance across the Central Pacific.