"Encyclopædia Britannica: Tian" "Encyclopædia Britannica: Tian" "Encyclopædia Britannica: Tian" "Encyclopædia Britannica: Tian" "Encyclopædia Britannica: Tian" "Encyclopædia Britannica: Tian" "Encyclopædia Britannica: Tian" "Encyclopædia Britannica: Tian" http://www.britannica.com/topic/tian