King Jigme Singye Wangchuk of Bhutan Monday publicly formalized a marriage to four sisters he wedded in private nine years ago and named the eldest of his eight children heir to the throne of the tiny Himalayan nation, a Bhutan Embassy official said.

The official said the traditional hourlong Buddhist ceremony was performed as scheduled at an ancient monastery in Punakha, the former capital of the isolated nation of 1.3 million people between India and Tibet in the eastern Himalayas.