That a inscribed Tiara exists (there are many Tiaras, some behind glass, some destroyed) with a certain phrase has been hotly contested by the Vatican, which is running damage control on the issue.
The self-imposed title was admitted in the April 18, 1915 issue of Our Sunday Visitor as being inscribed on a Pope's triple tiara which crowns him King of heaven, earth, and the realms below.
Here is a picture of one worn by Pope Pius IX inscribed with phrases that translates as:
To The Infallible Vicar of Jesus Christ
To the Supreme Governor of the World on Earth
To the Father of Nations and Kings