Ruben Saillens (1855-1942) is a well-known unknown figure in the Musée du Désert, not only for the worship services he led in the Cévennes but also as the author of the hymn La Cévenole, traditionally sung to open the annual Assemblé du Désert conference.

Saillens was born in Saint-Jean-du-Gard to Cévenol parents whose families had been influenced by the Revival and were members of the Evangelical Free Church of the Darbyites. Sensing a call to evangelism, he in 1873 met Rev. Robert McAll, who had recently established the Mission aux ouvriers de Paris. The next year Saillens himself joined the mission, and grew to become one of its linchpins. In 1878 he founded a mission in Marseille after the Parisian model, which grew very rapidly and opened many new chapters along the Mediterranean coast. In 1883, the missions of Saillens and McAll were fused under the new name Mission Populaire Évangélique. Saillens then returned to Paris to be near his mentor. In 1888, he founded a Baptist church, but from 1890 onwards he began to distance himself from the mission. Several years later, Saillens cut off all remaining ties.

A convinced Baptist, Saillens had a rich pastoral and evangelical ministry which he exercised in an independent manner in each church that reached out to him, regardless of its denominational affiliation. He established tent missions and Christian conventions, and founded the interdenominational Institut biblique of Nogent-sur-Marne in 1921.