If you want to have all the Venues avaialable (or almost all of them) you should start 18 months prior to the Wedding. Some highly requested venues are reserved very early, sometimes 2 years before the marriage. I sometimes work with couples who decide for their marriage just 3 months earlier. We can do it, no problem as we boast a large number of Wedding Venues in Italy. The choice is obviosly narrow with such a short time, but it will still be amazing!