The father of 3 was seventh in line to the throne and the third son of the reigning Prince Hans-Adam II.. Prince Constantin of Liechtenstein, a prince from one of Europe’s oldest royal families, died suddenly on Tuesday at the age of 51. The father of three was seventh in line to the throne and the third son of the reigning Prince Hans-Adam II. A cause of death has not been released. Liechtenstein, a tiny German-speaking nation, is located in the Alps and is landlocked between Austria and Switzerland. It has a population of just under 40,000 and is considered...