The development of these mills grew until the 18th century: there were 11 paper factories employing 500 people in the Vaucluse around this time. Of these 11 sites, 4 were established at Fontaine de Vaucluse. The first mill to be established on the banks of the river Sorgue was that of the Martinet mill in 1522. It was transformed into a silk factory in the 16th century, and then used for wool production in the 19th century. However it was returned to its original paper making role around 1920, following its purchase by Valdor-Prioux. Like most paper production sites in this region, the Martinet mill ceased production in 1968. At the end of the 16th century the Pont mill was built nearby with 2 water wheels. Around 1653 the Martinet Company built a second mill, the Fond mill, in order to cope with demand. In the 19th century the Pré mill was also established. However it served as an annexe for the Martinet mills and also ceased production in 1968. The last mill to be built near the river Sorgue was that of the ‘Chemin de la Fontaine' in 1862. This site would have suffered the same fate as the others if it was not for combined efforts that gave it a new lease of life.