The mother of all "it" bags is going on sale. Jane Birkin's Hermes bag, which spawned one of the most-coveted fashion items in history, will be up for auction next month.
Part of Sotheby's Fashion Icons sale, the online auction on July 10 will be held in parallel with the Paris Haute Couture Week.
Created 40 years ago for the late British singer and actress by French fashion house Hermes, the Birkin is one of the most sought-after handbags in the world today – with rare models fetching millions of dollars at auctions.
The actress was gifted five Birkin bags over the years, but she used the original prototype for about 10 years before putting it up for an Aids charity auction in 1994. It was subsequently sold again at auction in 2000 and has been in private hands ever since.
The bag was only seen again in public for the first time last year at Sotheby's Paris, attracting thousands of visitors.
Ahead of its sale, here are six things to know about The Original Birkin.
Origin story
At the peak of her popularity, Birkin had an encounter with Jean-Louis Dumas, the then chief executive of Hermes, in the first-class cabin of a flight from Paris to London.
Birkin was carrying a wicker purse, but its contents spilt out over the plane floor when she attempted to place it in the overhead locker. As Dumas began to assist her, Birkin complained she was unable to find a suitable leather weekend bag that would hold all the essentials.
And the rest is fashion history. Borrowing elements from Hermes’s existing sac Haut A Courroies, the finished all-black bag was eventually delivered to Birkin in 1985.
Birkin's initials

The original Birkin is branded with her initials JB on the front flap of the bag, below the lock. The bag would become Birkin's favourite accessory and was inseparable from her. "She would usually cradle it with both arms and took it with her everywhere," Sotheby's says.
Shoulder strap

The original Birkin is the only model with a non-removable shoulder strap, a design element that has not been retained in other Birkins. Only one limited-edition Birkin with a detachable shoulder strap was produced in the 1990s.
Nail clipper

Famed for her tomboyish dress sense and casual style, Birkin hated long painted nails and so she had a nail clipper on a chain hanging from the base of the shoulder strap, inside of her bag, for easy access and regular use.
Condition of the bag
The original Birkin is being sold in the exact condition in which Birkin had left it. An activist acutely aware of the power her image carried internationally, she also used her bag as an eye-catching placard to promote causes and organisations close to her heart, such as Medecins du Monde (Doctors of the World) and Unicef. The bag still bears the marks of the stickers she pasted on to it.
Seven key features
As a prototype, the original bag features key design elements that differentiate it from other commercially-produced Birkins. These include the size and the use of hardware. For example, the original Birkin features gilded brass hardware, which was replaced by gold-plated hardware when the first series of Birkin was launched in 1986.
Bidding on all items from the Sotheby's Fashion Icons sale begins on June 26 and closes on July 10