The construction materials of the Han Dynasty
The construction materials of the Han Dynasty unearthed from the Han Yanling Mausoleum include barrel tile, pan tile, eaves tile, rectangular brick, brick with flower pattern, apron, which manifest to the world that once many mausoleum constructions were established on the ground. Among them, the hollow bricks with four auspicious animals are the most eye-catching ones. The four auspicious animals refer to blue dragon, white tiger, scarlet bird, turtle with serpent, which symbolize four directions. In the Shang Dynasty when people observed the celestial bodies, they divided the starry sky into four parts with four auspicious animals as the symbol of the different astrology, which means blue dragon for east, scarlet bird for south, white tiger for west, turtle with snake for north. In the Han Dynasty the patterns of four auspicious animals were made on the construction materials and built on the palace, hall, gate-tower and pavilion to symbolize directions. The barrel tiles of Han Yangling are about 50.6cm long and 16.2cm wide, while those with eaves tiles measure more than 57cm in length. The diameter of eaves tiles are as long as 18cm and can be classified into those with patterns and with inscriptions. The patterns on the eaves tiles are mainly cloud ones with standard patterns and graceful lines. The eaves tiles with inscriptions are mainly inscribed with auspicious words, including eternal happiness and longevity. The auspicious words were arranged symmetrically into four sectors divided by double lines, showcasing both calligraphy and decoration values.