The simple preposition a in Italian has a multitude of uses. The preposition a is often used before particular cities or places:
but in Toscana
The following places and locations are also used with the preposition a:
a casaat home
a letto in bed, to bed
alla stazione at the station
Note that almost all the simple prepositions - except per and fra/tra - combine with the definite article.
The preposition in is used with regions and countries (in Toscana, in Italia).
Note that in some of these constructions, the definite article is not used.