 After the Congress of Vienna, the various Italian states reverted to their original system of measurements, but in 1845 the Kingdom of Piedmont and Sardinia passed legislation to introduce the metric system within five years.By 1860, most of Italy had been unified under the King of Sardinia Victor Emmanuel II and under "Law 132 of 28 July 28, 1861" the metric system became the official system of measurement throughout the kingdom.Numerous "Tavole di ragguaglio" (Conversion Tables) were displayed in shops until 31 December 1870.