Quite a few people won't understand what the City of London is about, since it comprises the financial district of the U.K., and goes back before the Norman Conquest (1066, which is probably why they were graned special rights above all others). Although this is supposition on my part (and others) it is thought to go back to the time of the Roman Empire, when they occupied ares of the British Isles, and established various short-term corporations to undertake various infrastructure building missions.
Now the City of London is owned by the City of London Corporation, which not only is the oldest but continuous existing corporation in the Western Hemisphere, if not the planet. They control the City of London Police, and the Queen, prior to entering that district, must first have a royal audience with the Lord High Mayor of London (as opposed to the other mayor, the mayor of the entire city of London) --- this has long been traditional and sacrosanct.
The City of London Corporation also has the oldest and continuous existing financial investment fund (forgot their name for it, sorry), and several bits of circumstantial evidence only, suggests they invested in some backward street and real estate in New Amsterdam, later to be known as Wall Street of New York City.
Now many may wonder about the relationship between the British royals and the City of London Corporation? Sometime around the early 1700s, the CoLC bought off the royal family by offering them, in perpetuity, leases on the choicest real estate throughout London, and outlying areas, based upon the cheapest discount RE rates of that day --- in other words, the CoLC leased out those lands to the royals, for a few shillings, a rate never to change, while the royals in turn would lease and rent out those lands and abodes for massive amounts over the centuries, especially in modern times.
Of course, this perpetuity thing was changed some years back, so now (I believe) it is only for 2,000 more years!
If you believe this to be farfetched, simply read a UK travel book or brochure some time, which is where I originally learned of this.
Oh, yes, shortly after this lease deal was sealed between the royals the CoLC, the Bank of England was established. (Think that may have been part of the deal?)