Korean War (1950–1953) 1950 North Korean Communist forces invade South Korea(June 25).UN calls for cease-fire and asks UN members to assist South Korea(June 27).Truman orders U.S. forces into Korea(June 27).North Koreans capture Seoul(June 28).Gen. Douglas MacArthur designated commander of unified UN forces(July 8).Pusan Beachhead—UN forces counterattack and capture Seoul(Aug.–Sept.),capture Pyongyang, North Korean capital(Oct.).Chinese Communists enter war(Oct. 26),force UN retreat toward 38th parallel(Dec.). 1951 Gen. Matthew B. Ridgway replaces MacArthur after he threatens Chinese with massive retaliation(April 11).Armistice negotiations(July)continue with interruptions untilJune 1953. 1953 Armistice signed(July 27).Chinese troops withdraw from North Korea(Oct. 26, 1958),but over 200 violations of armistice noted to1959.