The Simplon Road (more prosaically, State Road 33) has an intriguing history and is also famous for the dramatic landscapes before, on and after the Pass. Its construction was started by order of Napoleon in 1800, and it was intended as a section of the long road which was to link Milan and Paris.
It was built partly by using existing paths, which were joined together and widened, and partly by creating completely new stretches.
However, the origins of the road go back to 196 AD, when the Emperor Septimius Severus laid out a mule-track along the route, which ended near the border, thus not allowing a link with Octodurus (now Martigny), the capital of the Roman region of Civitas Vallensium. After the Romans stopped ruling the Valais territory, the Simplon track fell into disuse.
The route of the Simplon road starts from the Arch of Peace (also built by Napoleon) in Via Sempione in Milan, follows Corso Sempione and Via Gallarate, continuing through various towns in Lombardy and Piedmont, until it arrives in Iselle on the border between Italy and Switzerland. In the Valais canton in Switzerland it becomes National Road 9, and ten kilometres farther on is the tiny village of Simplon Dorf, which gives its name to the whole pass. After the Pass the road descends to the town of Brig in the Valley of the Rhone.
There are many interesting aspects of this “Imperial” road: from its astonishing width of eight metres, even in its Alpine sections, to the original adoption of the parabola curve in designing the bends, from the evenly rising gradient, to the guard stones made of stone.