It was only after 440 A.D. that December 25 was celebrated as the birth date of Jesus Christ. The first aerial photograph was taken from a balloon during the U.S. civil war. Olive oil was used for washing the body in the ancient Mediterranean world. In 1801, 20 percent of the people in the U.S. were slaves. Slaves under the last emperors of China wore pigtails so they could be picked out quickly.