A member of the Christian Democracy (DC), he served as the 39th prime minister of Italy from December 1968 to August 1970 and again from July 1973 to November 1974.

[4] He attended the classical lyceum Antonio Pigafetta in Vicenza, then he earned a degree from the University of Padua in literature in 1939.

Subsequent to the Armistice of Cassibile in 1943 between Italy and the Allied powers, Rumor joined the Italian resistance movement.

[14] In 1950, Guido Gonella succeeded Paolo Emilio Taviani as National Secretary of the DC; the target of the new secretariat was to build a unitary management of the party in support of the government led by Alcide De Gasperi.

[15] The withdrawal from politics of Giuseppe Dossetti, left his faction without a charismatic leader; however, Mariano Rumor played a decisive role in the birth of the new faction, called "Democratic Initiative", which brought together not only Dossetti's followers, such as Giorgio La Pira, Amintore Fanfani and Aldo Moro, but also members of the centrist pro-De Gasperi majority, as Paolo Emilio Taviani and Oscar Luigi Scalfaro.

[17] In this text, alongside the declaration of support for De Gasperi and the Atlantic Pact, Dossetti's principles of a Christian reformist party were reaffirmed, with the aim of moving the country towards a "democratic evolution".

In fact, many members of the faction, started criticizing the political line of Fanfani's secretariat, who cautiously began to open to the prospect of a collaboration with Italian Socialist Party (PSI).

[22] Prominent members of the faction, including Rumor himself, put the Secretary in minority during the National Congress of March 1959.

In this way, Democratic Initiative split up between the followers of Fanfani and the dissident group, now renamed by all Dorotei ("Dorotheans"), from the place where they had gathered before the congress, the convent of the sisters of Santa Dorotea in Rome.

[29] In the previous months, the Adriatic Society of Electricity (SADE) and the Italian government, which both owned the dam, dismissed evidence and concealed reports describing the geological instability of Monte Toc on the southern side of the basin and other early warning signs reported prior to the disaster.

[30] Immediately after the disaster, government and local authorities insisted on attributing the tragedy to an unexpected and unavoidable natural event.

[34] In the five years leading the DC, Rumor tried to reassure the moderate electorate, in an attempt to recover the consensus lost in the previous elections.

[35] Rumor embodied the typical characteristics of the Dorotheans: caution, moderation, the propensity for mediation rather than for decision, attention to practical and concrete topics, rather than to major strategies, the representation of the interests of the provincial middle class, the privileged link with the public administration, with the Catholic world and with direct farmers.

On 13 December 1968, Mariano Rumor was sworn in as prime minister for the first time, leading a government composed of Christian Democrats, Socialists and Republicans.

[40] The attack was planned by a neo-fascist group, Ordine Nuovo ("New Order"), whose aim was to prevent the country falling into the hands of the left-wing by duping the public into believing the bombings were part of a communist insurgency.

[45][46] During his second term, the Parliament approved a law on 2 March 1974, with which legal minimum for pensions was raised to 27.75% of the average industrial wage for 1973.

[50] During his ministry, he signed the Osimo Treaty with Yugoslavia, defining the official partition of the Free Territory of Trieste.

[51] The Italian government was harshly criticized for signing the treaty, particularly for the secretive way in which negotiations were carried out, skipping the traditional diplomatic channels.

[53] Some nationalist politicians called for the prosecution of Prime Minister Moro and Minister Rumor, for the crime of treason, as stated in Article 241 of the Italian Criminal Code, which mandated a life sentence for anybody found guilty of aiding and abetting a foreign power to exert its sovereignty on the national territory.

[57] The Lockheed bribery scandals, of which Rumor was exonerated by the Italian Parliament, took place under his government and culminated in the trials of two former Defense ministers, Luigi Gui and Mario Tanassi.