With only three issued at any one time, the Sovereign Military Order of Malta is thought to have the obscurest passport in the world.
The Catholic order's passports are only issued to its three highest officers - the Grand Master, Deputy Grand Master and Chancellor.
As mentioned on question-and-answer website Quora, all other officers of the order use the passports issued by their home countries.
Given its full title, the Sovereign Military Hospitaller Order of Saint John of Jerusalem of Rhodes and of Malta originated as the Crusader Knights Hospitaller in 1099.
Since losing the island of Malta in 1800, this military order's sovereign land is restricted to two extra-territorial properties in Rome, from where it issues its own postage stamps, currency and passports.
Currently this Catholic order operates as a charitable organisation offering medical aid across the world.
It is made up of over 13,500 Knights, Dames and Chaplains along with 80,000 permanent volunteers and 25,000 employees.
The order has diplomatic relations with 106 different countries including the Spain, Russia and United States.
Countries that do not accept the order's passports include the United Kingdom, the United States and New Zealand.
The current Grand Master is Fra' Sir Matthew Festing, the second Englishman to occupy the role since 1259.
