The term "Middle East" may have originated in the 1850s in the British India Office. However, it became more widely known when American naval strategist Alfred Thayer Mahan used the term in 1902 to "designate the area between Arabia and India". During this time the British and Russian Empires were vying for influence in Central Asia, a rivalry which would become known as The Great Game. Mahan realized not only the strategic importance of the region but also of its center, the Persian Gulf. He labeled the area surrounding the Persian Gulf as the Middle East and said that after Egypt's Suez Canal, it was the most important passage for Britain to control in order to keep the Russians from advancing towards British India. The first official use of the term "Middle East" by the United States government was in the 1957 Eisenhower Doctrine, which pertained to the Suez Crisis. Secretary of State John Foster Dulles defined the Middle East as "the area lying between and including Libya on the west and Pakistan on the east, Syria, and Iraq on the North and the Arabian Peninsula to the south, plus the Sudan and Ethiopia."