Large numbers of men from Ireland joined the Papal Army in Italy to defend the Papal States. This list contains the names of those who volunteered and in some cases their address.
The majority of names, however, did not contain address information, only the addresses of those who recommended the issue of a passport were recorded.
While it is thought that they would have both come from the same area, this is not certain and the address field therefore contains a question mark.
For more information see the Fifty-ninth report of the Deputy Keeper of the Public Records in Ireland.