Latin
Probably not, but he can if he wants to.
a king Charles spaniel with another king Charles spaniel
The possessive form is King Charles's laws.
King Charles II
The Cavalier King Charles Spaniel received its name from King Charles II.
...King Charles the 2nd...
Charles I was the English king who granted land to Maryland. Charles was later executed in 1649 after a struggle with Parliament.
The king was King Charles
a King Charles spaniel is called 'un épagneul King Charles' or 'un King Charles' in French.
King Charles enjoyed hunting
king Charles II (2nd)was king in 1666
I am not quite sure but I think IF Charles keeps his name as Charles it would be C.R for Charles Rex, Latin for King Charles with an III in the middle. However, apparently he will change his name to George meaning they will be G.R for George Rex with a VII for 7th as he would be Charles 7th