Ramón de Pignatelli was an "enlightened" man. He was prime minister in the 18th century. The works for the irrigation system were started in 1738, but didn't go very fast until Pignatelli was in charge. They got as far as Zaragoza in 1786, commemorated by the "unbelievers' fountain"; nothing to do with religion but to celebrate a work of engineering delayed for a couple of centuries and which some people believed would never bring the water to Zaragoza.
Wikipedia says: "When Ramón Pignatelli started to build a canal from the Cantabrian sea to the Mediterranean, many people laughed at the idea. When the waters reached Zaragoza, he ordered a fountain to be built to celebrate it, as the inscription says: "to convince the incredulous and to relieve passers-by" ("Incredulorum convictioni et viatorum commodo" Anno MDCCLXXXVI) Thus the fountain was proof of the success of the enterprise and a joke directed towards those who had not believed it was possible."
