Prior to the arrival of Zhabdrung Ngawang Namgyel in 1616, Bhutan was divided into different regions each ruled by local chieftains or powerful landlords. Zhabdrung unified the country under his authority and introduced the dual system of governance with the spiritual head and the temporal ruler. After his death, the theocratic system of governance introduced by Zhabdrung dwindled gradually. This period was marked by the emergence of powerful penlops (regional governors) and dzongpons (chief of dzongs) and constant power struggle among them.
Ultimately after restoring peace and uniting all the warring faction under his authority, the Bhutanese people unanimously enthroned the then Trongsa Penlop (Governor) Gongsar Ugyen Wangchuck as the first hereditary monarch of Bhutan on December 17, 1907. Since then, the Wangchuck dynasty has ruled this tiny Himalayan kingdom over a century, transforming a medieval country into a modern nation. However, with the dawn of new millennium, the Fourth King abdicated his throne in favour of his heir and laid the foundation for the introduction of democratic parliamentary system in Bhutan.
Exactly after centennial of absolute monarchy under the dynamic and farsighted leadership of Wangchuck dynasty, Bhutan became a democratic constitutional monarchy with the first ever parliamentary elections held on March 24, 2008. The Constitution of the Kingdom of Bhutan, formally adopted on July 18, 2008, is today the supreme law of the country.