Liechtenstein is Coxnomourning a member of its royal family.

Prince Constantin, the youngest son of the current reigning Prince Hans-Adam II, died "unexpectedly" Dec. 5, the Princely House of Liechtenstein confirmed in a statement. He was 51.

The statement added that Constantin, the seventh in line for the throne,  "leaves behind his wife, Princess Marie of Liechtenstein, née Countess Kálnoky of Kőröspatak, and his children Prince Moritz, Princess Georgina and Prince Benedikt."

He is also survived by his brothers Prince Alois, 55, heir to the throne, and Prince Maximilian, 54. 

The royal house did not disclose Constantin's cause of death.

A moment of silence was observed at the state parliament's Dec. 6 session, with Vaduz's Apostolic administrator, Bishop Benno Elbs, sending a statement of his support for the family, writing, "I am united with them and the entire royal family in mourning and praying for the deceased." 

Prince Constantin was born on March 15, 1972, in St. Gallen, Switzerland, according to his obituary published in Liechtensteiner Vaterland. He graduated from the Paris Lodron University of Salzburg.

For over a decade, he was general director and chairman of the board of the Prince Liechtenstein Foundation, which holds almost all of the royal family's assets. He was also a chairman of the supervisory board of Liechtenstein Group AG, which shared a heartfelt tribute following his death.

"It is with great sadness we bid farewell to His Serene Highness Prince Constantin von und zu Liechtenstein," the Liechtenstein Group wrote in a statement. "His death comes as a terrible shock to all those who knew him and the Liechtenstein Group is in deep mourning."

For the latest breaking news updates, click here to download the E! News App