Several other Royals didnt come either.
(Who was entitled as an Ellected Monarch of The Vatican
city State, however, he visited not so long ago, is quite old, and his travels might have garnered too much attention and danger as hosts.
was not invited probably because he took power via a coup and runs his ship like a captain
was not invited to attend possibly because his countries geography would make travel difficult and he'd almost certainly be reluctant to leave
Was not invited to attend pol pot noodle anyone
Aparently Monaco has the longest reigning Monarch in Europe (although the invited guest was his successor) The Thai Crown is worn by the worlds longest reigning Monarch...he's still very much alive...and Denmark earns the reward of longest continuous monarchy, whilst we have longest monarchy (the problem is that the first 500 years arguably their were three crowns covering different parts of England, and of course the embarissment of the Protectorate after the Civil war...there are arguments to say as the Kings son was never killed the line remained unbroken and he was king, but he rulled in exhile...depends how you view it