They managed to convince Fiat to let them have the original prototype of the Fiat Seicento designed by Dante Giacosa, manufactured in 1952. It is worth remembering that the final car was presented in 1955, as the tool that would revolutionize mobility in post-war Italy. This initial prototype had many similarities with the definitive 600, although it had a twin-cylinder engine (the final production model would end up using a four-cylinder engine, as you know).
In 1957 the Sociedad Española de Automóviles de Turismo, SEAT, would start production of the 600 in our country, under a Fiat license. And well, the rest is history, as they say. But it's nice to look back and see the "grandfather" of that car that changed our history, in one of its early stages of development as "Project 100", when, in fact, it still didn't have the green light from the board of directors to go into production.