A trade route across the mountain passes to the Gastein Valley in the north may already existed in the Bronze Age. It was used by the Celts from about 400 BC, and when the area was incorporated into the Roman Noricum province about 15 BC, these bridle paths were rebuilt as a Roman road.
There might have been an ancient trade route across mountain passes to the Gastein Valley in the north dating back to the Bronze Age. The Celts employed this path from roughly 400 BC, and when the area was annexed by the Romans around 15 BC, these trails were revamped into a Roman highway.