Chokhor Raptse Dzong at Trongsa which was built in 1644, used to be the seat of power of the Wangchuck dynasty before it became rulers of Bhutan in 1907. Traditionally the King of Bhutan first becomes the Trongsa Penlop(governor) before being named Crown Prince and eventually King. Built on a mountain spur high above the gorges of the Mangde Chhu, the dzong controlled east-west trade for centuries. The only road connecting eastern and western Bhutan (the precursor to the modern Lateral Road), passed through the courtyard of the dzong. At the command of the penlop the massive doors could be shut, dividing the country in two.