In 1943, with World War II at its height, King Boris III of Bulgaria died. Rule passed to his son, who ruled as Simeon II from 1943 until the monarchy was abolished in 1946. Simeon was forced into exile for the duration of socialist rule.

Bizarrely, Simeon later returned to Bulgaria, entered politics, and became Prime Minister of Bulgaria between 2001 and 2005. So he became the democratically elected leader of the country whose throne he had abandoned nearly 60 years earlier.

Simeon in 2017. (Image: Grey Geezer on Wikipedia)

It must be the greatest span of time between two stints ruling a country. It’s helped, of course, by the fact that he ascended to the throne aged six, but it’s still a crazy length of time.