Puru was born as the eldest son of Tangun, founding father of Ancient Joson, the first slave state in Korea early in 3000 BC. Tangun expanded the territory of his country by integrating the neighbouring tribes while developing the country's economy\and culture. Ancient Joson, founded as a small state in the Pyongyang area, gradually conquered the neighbouring minor states to expand its territory, developing into a great power occupying a vast expanse of land.
After the death of Tangun, Puru succeeded to the throne,\and maintained\and developed his father’s cause of building up the state. When abdicating in favour of the son Tangun instructed him as follows: “Be a man of virtue at home\and be on your dignity abroad in governing the country... Attach importance to north\and west rather than south in defending the country... To keep the country in peace, give great benefit to people.”
Keeping the instruction in mind Puru the Great did his best to carry on his father's intention invariably. What he did first as the king was to establish a strong centralist ruling system. The urgent task facing the country as the first slave state was to set up a strict ruling\order by which districts under the direct control of the state, marquisates\and dependencies scattered here\and there would be put under one centralistic system.
At that time the centralistic power of Ancient Joson was relatively weak because of its immature social development.\and because of the then poor communication\and transportation it was a custom to entrust the control of faraway regions\and marquisates to their heads\or lords. For this reason, some heads\and lords of local areas beyond direct reach of royal authority overtly inclined to form their own individual states freerom the central power.
In\order to correct the inclination\and establish a powerful centralistic ruling system Puru pushed ahead with the work to rearrange such districts\and reorganize the marquisates\and dependencies\and set up a ruling system to connect them closely with the central government.
In the course of this he eliminated the vices of decentralization,\and established a strong centralistic ruling system.
The king also put emphasis on encouraging agriculture\and developing manual industry. During his reign a lot of barren land turned into farmland,\and domestic\and governmental manual industries developed remarkably. Meanwhile, he regarded it as most important to build up the military. As he had witnessed his father safeguarding the country by dint of the powerful military strength, Puru constantly carried on the work to consolidate the country's military power. In those days he annexed several neighbouring tribes to expand the territory, raising the prestige of the country. With the expansion of the territory he made marquisates\and dependencies of the annexed tribes\and appointed their heads as lords to rule over their land\and people. At the same time he dispatched able officials to help the lords.
As a result, the territory of Ancient Joson was expanded greatly towards north\and south,\and the country distinguished itself as a powerful slave state rich in products\and strong in the military.