A few years ago, Finlay Glen received a letter at his home on Hamlet Road in south London that was addressed to a Mrs. Oswald Marsh. By that time, the former occupant of the house was long gone.

At first, Glen didn't realize just how old the letter, which was in amazing condition, was. But a quick look at the stamp with a picture of King George V told him that it was more than a few years late in being delivered.

Finlay Glen told CNN,

We noticed that the year on it was '16. So we thought it was 2016. Then we noticed that the stamp was a King rather than a Queen, so we felt that it couldn't have been 2016.

The letter was indeed mailed in 1916, in the middle of World War I and years before the birth of Queen Elizabeth.

They have no idea how the letter came to be delivered over 100 years after it was sent.

A spokesperson for the Royal Mail said,

Incidents like this happen very occasionally, and we are uncertain what has happened in this incident. We appreciate that people will be intrigued by the history of this letter from 1916, but have no further information on what might have happened.

Glen recently passed the letter on to historian, Stephen Oxford, who is the editor of a local magazine called the Norwood Review.

Oxford told CNN,

As a local historian I was amazed and delighted to have the details of the letter passed to me.

The intended recipient was the wife of a stamp dealer, Oswald Marsh, and the author of the letter was the daughter of tea merchant Henry Tuke Mennel, who wrote the letter on a piece of hotel stationary while on holiday in Bath.

Glen said that if the letter is of no historical significance, he would like to keep it for himself.

After all, it was delivered to his house!