In matters of inheritance, it’s essential that the heirs file the Succession Declaration (“dichiarazione di successione”) with the Revenue Agency within one year of the death (the opening of the succession). This declaration has a purely tax function, but it becomes the key document through which the transfer of rights and obligations from the deceased to the heir — including ownership — is later demonstrated.
An estate does not pass automatically from the deceased to the heir: the heir must accept it, expressly or tacitly. Acceptance has retroactive effect and is irrevocable.
Beyond this, proving ownership of the property requires a further step: the cadastral transfer (“voltura catastale”). It is indispensable in order to obtain the cadastral records that prove ownership of the property.
It often happens that, even though the succession declaration has been filed, when it comes to signing the deed for the sale of an inherited property, the correct chain of provenance and acceptance still has to be verified. Checking this in advance avoids delays at completion.
This article is for general information and refers to Italian law; for your specific case, always rely on a notary or qualified professional.