Short answers, pulled from the story.
The Kingdom of Italy was officially proclaimed on the 17th of March 1861 when Victor Emmanuel II of Sardinia became King in Turin. This event marked the birth of a new state from decades of struggle known as the Risorgimento.
Monarchs ruling the Kingdom of Italy included Victor Emmanuel II, Umberto I, Victor Emmanuel III, and Umberto II. These rulers governed from 1861 until the monarchy was abolished following an institutional referendum held on the 2nd of June 1946.
Poverty drove millions of Italians to leave their homeland starting around 1880 due to widespread rural poverty combined with overpopulation. Between 1876 and 1915 more than 14 million people emigrated primarily to North America South America Canada Australia and Latin American countries.
Mussolini abolished proportional representation using the Acerbo Law which granted two-thirds of seats to the winning party giving Fascist Party absolute control over the Chamber. By 1939 the Chamber of Fasces and Corporations replaced the Chamber of Deputies entirely while the Grand Council of Fascism took control of administration in 1928.
The House of Savoy lost power after an institutional referendum held on the 2nd of June 1946 which established the modern Italian Republic. Victor Emmanuel III abdicated on the 9th of May 1946 passing the crown to his son Umberto II who reigned briefly until the republic was officially proclaimed on the 12th of June 1946.