If I may...
March 17th
On March 17th 1861, in Turin, Victor Emmanuel II of Savoy was proclaimed "Re d'Italia per grazia di Dio e volontà della Nazione" (King of Italy by grace of God and will of the Nation). That was the end of Italian Unification Process.
P.S.
I know that's not an anniverary of birth or death (although something actually was born that day), but it's still an important date to rember (may be the most important date, for House of Savoy).