The Fourth King of Bhutan, Jigme Singye Wangchuck, married four sisters, known as the Four Queen Mothers, simultaneously. This decision was made to prevent family rivalry and maintain harmony within the royal family. It is also alleged that a prophecy foretold he would marry four sisters, descendants of Shabdrung Ngawang Namgyal, the lama who unified Bhutan in the 17th century. To fulfill the prophecy, he proceeded with the marriage.