The dream should have ended then, with the Welsh assimilated within a generation. Astonishingly it persisted. Many generations on from the first emigrants, the Welsh language can still be heard in Patagonia.
Despite having received no further emigrants from Wales after 1914, and despite the Spanish-only education system, Welsh remained the language of the homes, the chapels, the eisteddfodau.
And when, in the last decades of the 20th century, it started to show signs of serious decline, it was given an unexpected new lease of life. Cheaper air travel made communications with Wales much easier. More and more people from Wales began to visit. Measures were taken to support the language in its only outpost outside Wales.
In 1996 the Welsh Office began a programme, still continuing under the National Assembly, in which groups of teachers spend a year in Patagonia teaching the language. Some 700 people are currently enrolled in classes. A surprising number come to fluency. A British Council internet project keeps the groups of learners in touch with Welsh speakers in Wales. 21st century technology sustains a 19th century ideal.
Ann-Marie Brierly visited Patagonia as a teacher in 2001. One of her students was Fabio Lewis, whose great grandfather, Lewis Davies, had come over on the Mimosa. Soon, Fabio's relationship with the land of his fathers had reached an unexpected level of engagement, and he and Ann-Marie were married at her home village in south Wales in the summer of 2003.
"I wonder what my great grandfather and mother would have thought to know that a small part of them had come back to Wales to make a home here," says Fabio. Now he and Ann-Marie organise tours of Patagonia for the growing number of people from Wales who make the 8,000-mile trip.
Those visitors can tour Welsh-named communities such as Trelew, Trevelin, Puerto Madryn or indeed Fabio's home village of Dolavon. They can walk down streets named after "Miguel de Jones" (the Spanish for the founder, Michael D Jones), and see statues to the founding fathers of the colony. Visitors can attend a service in one of the Welsh chapels, sample tea and bara brith in one of the numerous Welsh tea houses, stroll round the Gorsedd circle in Gaiman, or attend one of the numerous eisteddfodau, now bilingual in Spanish and Welsh , which still thrive.
And if they can speak the 'language of heaven' they could pass the time of day with one of the many people who can still speak Welsh in this corner of South America, where a people's love of their culture and their religion proved that not even a desert can be stronger than a dream.
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