Ireland – Certificate of Freedom to Marry
This is a document stating that you are free to marry, which is required by some countries before you can get married. The Department of Foreign Affairs and Trade issues this certificate, which is also known as a Civil Letter of Freedom, Certificate de Coutume or Nulla Osta.
Official information and a link to apply for the certificate is available at the Department of Foreign Affairs website here: Certificate of Freedom to Marry
Ireland – Registering your marriage
If you marry abroad, it will only be recognised in Ireland if it is entered on the civil register of the country where the ceremony took place and provided all legal formalities have been followed.
Independently from your nationality, in order to get legally married in Italy you should be able to provide the following documents.
Italy – Other Documentation
Passports
Certificate of No Impediment
Italy – Time Limit
Applications to marry in Italy expire after three months. If your marriage does not take place within this time period, you will need to apply again.