Serene Highness

Serene Highness is a style of address used by several princely and noble families throughout present-day Europe. It has also been used historically. It ranks below Royal Highness and Imperial Highness.
is the title reserved for the princes of the sovereign princely families, currently unique the ruling families of Monaco and Liechtenstein. Some heraldists believe it is also due to the descendants of the sovereign Principality of Sperlinga, who sold the Castle but kept the title, and it is from all its members.