In the old days, two routes linked the Lac Léman basin and our neighbouring country of France: one lead near Vallorbe and the other through Saint-Georges, La Givrine and Les Rousses (France). 

One fact we do know for sure: after the decadence of the Roman Empire, Vallée de Joux was uninhabited for several centuries. 

When Christianity thrust its way through, many religious installations were founded, some of which in really solitary and unapproachable locations, like Saint-Claude (France).
 
There was a constant traffic between Saint-Claude and the monastery of Romainmôtier, to which the shortest way passed through Vallée de Joux. The route was trying and some night halts were established, of which one was found in Le Lieu. 

The monk Dom Poncet was the first one who settled down in Le Lieu, at the end of the sixth century. History tells us that he distinguished himself by his virtue and many miracles.

The unity that was set up in the village of Le Lieu became important and the monastic life was very active as it consisted in a staging point for about 900 monks. However, in 610 Romainmôtier was destroyed by the Alemans. The religious life quickly came to an end. We do not know how far the Aleman hordes went, but the ruins in Le Lieu date from this epoch.
 
The only relic left from this era is the Fountain of Dom Poncet. 

Today, the village of Le Lieu lives by agriculture and industry. Well-known industries within high-class chronograph- and watchmaking as well as precision-tool making have been established.