In spite its great fame, Tiramisù is very young and it was invented less than 100 years ago. Its name became famous in the 1980s, when the recipe also started to spread.
Several legends rotate around the Italian dessert and its creation. For instance, rumours say that Tiramisù was invented in Siena (Tuscany) in the 17th as a treat to please Grand Duke Cosimo de Medici. Nevertheless, this story seems to be quite imprecise because mascarpone (the main ingredient of Tiramisù) was invented in Lombardy and it was not known in Tuscany at that time.
Fonte: This is Italy