The Pentaverate is first mentioned in So I Married an Axe Murderer (1993) (1993) by Charlie's father. The deep conspiracy claims the group of five run the world meeting triennially at a secret country mansion known as "The Meadows".
In So I Married an Axe Murderer (1993), Stuart Mackenzie (Mike Myers) named the members of the Pentaverate as "The Queen, the Vatican, the Gettys, the Rothschilds, *and* Colonel Sanders before he went tits up."
'The Meadows' interiors were actually filmed in the Freemasons Hall, the Grand Lodge of England, London.
Paul Myers, credited as Additional Crew, is Mike Myers' brother. Mike had his brother Paul play his body double/stand-in for his characters (like Oscar Isaac had his brother, Michael Benjamin Hernandez, do in Moon Knight (2022) (2022)). Paul Myers also famously played a frozen Austin Powers (double) in the Austin Powers movies.
The secret underground railway between New York and Dubrovnik is in reality the London Post Office Railway which transported post beneath the streets of London from 1927 until 2003.