From a historical perspective – one of the most important elements in tracing the route – the reference used was a map published in 1963 in a book by economist Armando Frumento, titled “Imprese lombarde nella storia della siderurgia italiana” (Lombard enterprises in the history of the Italian iron and steel industry).
In this work, under the heading “Vie di comunicazione siderurgica della Valsassina nel Settecento” (Routes used in the 18th century for the transport of iron and steel in the Valsassina valley), it can be seen that the two main trading routes for iron ore both into and out of Valsassina, as part of the “Terre di San Marco” (Lands of St. Mark), were:
1) the river Stabina Way at the foot of the valley, from Olmo al Brembo to Valtorta;
2) the “high altitude” Way from Averara/Santa Brigida to Cusio and Ornica. These paths were repeated and confirmed by maps both dating back to those times and later on, right up to the surveys made by the Military Geographical Institute at the end of the 19th century.
The route presented here retains these historical characteristics, which are in part also reflected by the physical structure of the respective paths, further validating its authenticity.