At one time no Chinese Emperor would dream of leaving his palace without first checking with his astrologers that fortune was on his side. Every moment of his day was governed by their predictions. As a result of this the Emperor Shen Tsung in about 1100 AD decided to build the most perfect clock the world had ever seen. He assigned the task to his minister Su Sung who, after several years, came up with a water-powered clock that not only told the time of day, but the date, month and a host of other things as well.