Scholars have traditionally traced its bronze-casting technology to northern China. This theory was based on the assumption that bronze casting in eastern Asia originated in northern China; however, this idea has been discredited by archaeological discoveries in north-eastern Thailand in the 1970's. In the words of one scholar, "bronze casting began in Southeast Asia and was later borrowed by the Chinese, not vice versa as the Chinese scholars have always claimed". Such interpretation is supported by the work of modern Vietnamese archaeologists. They have found that the earliest bronze drums of Dong Son are closely related in basic structural features and in decorative design to the pottery of the Phung Nguyen culture.
It is still uncertain whether the bronze drums were made for religious ceremonies, to rally men for war, or for another secular role. Most of the bronze drums were made in Viet Nam and South China but they were traded to the south and west such as Java and Bali islands, and were valued by people with very different cultures. The Dong Son bronze drums exhibit the advanced techniques and the great skill in the lost-wax casting of large objects, the Co Loa drum would have required the smelting of between 1 and 7 tons of copper ore and the use of up to 10 large castings crucibles at one time.
Most scholars agree the Dong Son drums display an artistic level reaching perfection that few cultures of the time could rival. The Dong Son drums, especially the early ones, were decorated with very rich and well composed images of objects, humans and animals. These images together provided a lively description of the Dong Son society, its people, their daily chores as well as their spiritual life and ceremonial activities.
The decorative images on the tympanum follow a common pattern: at the center is a star encircled by concentric panels of human or animal scenes interspersed with bands of geometric motifs. Birds, deers, buffaloes and hornbills were depicted. Historians have identified the connection between Van Lang and the word vlang (or blang), a large bird in the Austro-Asiatic Viet language. Furthermore, the Hung kings also chose a heron, an aquatic bird, as the totem of Van Lang.
The Dong Son society was an agricultural one based on the wet
rice cultivation. The images on of the Dong Son drums vividly
described the activities associated with rice production such
as people carrying plows, buffaloes and oxen working the fields
and farmers milling rice with hand pestles.
Water rituals were well depicted on the face and body of the drums. Scenes of boat race are believed to represent village festivals to celebrate the supreme role of water in agriculture. Images of Dong Son warriors and their weapons are found carved on many drums. Many types of weapon were represented: cross-bow, javelin, hatchet, spear, dagger and body shield. These images confirm the historical setting of the Dong Son time as its people was in constant fighting for survival against the people from the North.
Social events were well depicted on the drums through images of dancers, musicians and musical instruments. There were bronze drums, bells, castanets, the senhs (rattlers made of bamboo cylinders taped to the arm or leg to make sound when dancing) and the khens (instruments with 4 to 6 long pipes attached to a resonance box). On the Ngoc Lu and Hoang Ha drums, images of Dong Son people sit in line on the floor beating the bronze drums with drumsticks. Dancers in ceremonial garments processing in a counter clockwise direction, each dancer holding an instrument or a weapon with one hand while the other hand forms some sort of rhythmic gesture.