Learco Guerra was supposedly Benito Mussolini's favourite cyclist. He was from a humble background and had risen to the top of the world by showing 'manly Italian virtues' - exceptional strength, stamina, determination and, in his case some would say, stupidity. Mussolini's sons, Vittorio and Bruno were apparently big fans - and the favour was returned, Learco Guerra was more than happy to join the Partito Nazionale Fascista (PNF).
As a cyclist, Learco Guerra's speciality was holding a high speed for an alarmingly long time - an excellent way to win a time trial or even a Classic. He won the World Road Race Championship in 1931.
However he was no great climber and was not built for competing in the Grand Tours. After frustrating Il Duce's propaganda machine by repeatedly failing to win the Giro, the route of the 1934 race was mysteriously flat and, unusually, included two time trials. Learco Guerra seemingly rose to the occasion and, to widespread relief, won by 51 seconds from Francesco Camusso, who was whispered to be a socialist. The story goes that Camusso claimed that, on one climb, Learco Guerra had cracked, but Blackshirts had intervened and the race organisers had taken him back up to the peleton in the boot of a car.
After retiring Learco Guerra took the conventional step into team management and, most notably, managed two Tour winners, Hugo Koblet and Charly Gaul. But it is also notable that, after their retirement, neither of his stars found any peace. Perhaps Learco Guerra liked to work with edgy mavericks, or perhaps his regime, whether physical, psychological or pharmaceutical, unknowingly devoured its favourite children.
In terms of derailleurs, I think that Learco Guerra won his World's Road Race riding fixed.
This rather fetching shot from 1934 shows Learco cycling through the Bois de Boulogne togged up as if he is just off to shoot some grouse. It is one of two images of him on this site, the other is here.
(Source gallica.bnf.fr/ Bibliothèque nationale de France)