A Brief History of the Marque
The machine consisted of a large wheel within which were mounted both engine and rider, and reportedly it was capable of achieving 100 km/h. Presented at the Milan Trade Fair on April 12, 1923 with a 175cc two-stroke, it progressed to a 350cc Garelli split-single.
Cislaghi was a policeman in Milan. Popular Science Monthly reports that he won a bet by riding one of his monowheels from Milan to Rome and then riding it in front of the National Stadium in Rome.
Cislaghi was the founder of the Motoruota company, in partnership with Govetosa. Motoruota is Italian for "motorwheel", and it was by this name that the invention was better known.
The machines were demonstrated widely in Europe and as far afield as the United States, where a Motoruota achieved over 120 km/h before Cislaghi's nephew lost control and destroyed it.
It had many emulators, and there was even an armoured version offered for military service in 1933. The army said thank you, but no.
See also Garavaglia
Sources: MC Storico Conti, Wikipedia IT, et al