We all know that the ancient ruler is generally shorter than the present ruler, and the length is different in different times:
One foot of the weekly ruler is the current metric system 19.9 1 cm.
One foot in the Han Dynasty is now 23.33 centimeters in metric system.
One foot in the Qin and Han Dynasties is now 27.65 centimeters in metric system.
One foot in the post-Han, Wei and Jin dynasties is now 23.33 centimeters metric.
One foot in the Tang Dynasty is now metric 3 1. 1 cm.
One foot in the Song Dynasty is now 30.72 centimeters metric.
One foot in the Ming Dynasty is now metric 3 1. 1 cm.
One foot in the Qing Dynasty is now 32 centimeters metric.
Therefore, when we look at the height of the ancients, we should also pay attention to their age, and we can't use a unified standard to convert them.
For example, seven or eight feet in the Three Kingdoms is not necessarily very high, but 1 m 7 or so; Wu Dalang's five feet is five feet in the Song Dynasty, and there is actually a 1 m 5, which is a little short, but not a dwarf.
In addition, from the perspective of human evolution, the average height of modern people is higher than that of the ancients, and it is still growing. Therefore, after understanding the differences in ancient weights and measures, people will not feel that there were giants everywhere in the past.