'Of' indicates something's origin or composition. A bar of gold = a bar made from gold Mary of London = Mary, who comes from London (every person's name used to say where they came from in this manner, but has since been replaced by last names). George of the jungle = George, who is from the jungle It can be extended to possession: Marie's car = a car of Marie George's couch = the couch of George The son of Bill = Bill's son King of the jungle = The jungle's king Lord of the Rings = The rings' lord.