The Kingdom of Italy used this flag from its creation on 17 March 1861 until the abdication of its last king and the declaration of the Republic of Italy on 10 June 1946. The arms in the centre are those of the House of Savoy, the ruling family. They were removed in 1946. The flag is based on that of France.
The naval ensign had the royal crown above the arms. Today's naval and civil ensigns have a shield made up of the arms of Venice, Genoa, Amalfi and Pisa, with the naval ensign having a naval coronet above the shield (the arms of Venice vary slightly between the two ensigns).
Naval Jack [Ratio 4:5]
The jack was a banner of the arms of Savoy. Today's jack is the same arms as appear on the modern naval ensign.