It was on 02 June 1946 that the House of Savoy's monarchical rule over Italy ended when a referendum was passed with 54% of voters choosing to establish a republic.
King Umberto II didn't accept the results of the election and briefly considered establishing a new headquarters in Naples and claiming to still be the legitimate ruler -- Naples and nearby cities had voted to stay under a monarch -- but calmer (less orange) heads prevailed and he left the Quirinal Palace in Rome for the last time on June 13th and flew to Lisbon.
It's interesting to look at the charts showing the results of the voting in different provinces and then consider how those areas have fared in the succeeding years, economically and culturally:
https://en.wikipedia.org/wiki/1946_Italian_institutional_referendum
Umberto II lived the rest of his life in Cascais on the Portuguese Riviera, although he traveled a lot, especially to visit his daughter in Mexico. He died in 1983 in Geneva and is buried in a Savoy family abbey in France.