[1] Groza became Premier in 1945 when Nicolae Rădescu, a leading Romanian Army general who assumed power briefly following the conclusion of World War II, was forced to resign by the Soviet Union's deputy People's Commissar for Foreign Affairs, Andrei Y.

[2] Born as one of the three sons of a wealthy couple in Bácsi (now called Băcia), a village near Déva (today Deva) in Transylvania (part of Austria-Hungary at the time), his father Adam was a priest.

[2][3] During this period in his life, Groza was able to amass a personal fortune as a wealthy landowner[5] and establish a notable reputation as a prominent layman within the Romanian Orthodox Church, a position which would later make him invaluable to a Romanian Communist Party (PCR) that was campaigning to attract the support of Eastern Orthodox Christians who constituted the nation's most numerous religious group in 1945.

[8] In response, Andrey Vyshinsky, the Soviet vice commissar of foreign affairs, traveled to Bucharest and allegedly gave King Michael an ultimatum—unless he sacked Rădescu and replaced him with Groza, Romania's independence would be at risk.

He stated at a cabinet meeting on 7 March 1945, for example, that the government sought to guarantee safety and order for the population, implement desired land reform policies, and focus on a "swift cleanup" of the state bureaucracy and immediate prosecution of war criminals, i.e., officials of the Fascist wartime regime of Marshal Ion Antonescu (see Romania during World War II and Romanian People's Tribunals).

Years later, historian Petre Țurlea [ro] reviewed a confidential Communist Party report about the election that showed the BPD had, at most, won 47 percent of the vote.

On 10 March 1945, the Soviet Union agreed to return to Romania Northern Transylvania, a territory of over 45,000 km2 (17,000 sq mi) that had been assigned to Hungary through the 1940 Second Vienna Award sponsored by Germany and Italy.

He proceeded to eliminate any antagonistic elements in the government administration and, in the newly acquired Transylvanian territory, removed three city prefects, including that of the region's capital, Cluj.

Groza also promised a series of land reform programs to benefit military personnel, which would confiscate and subsequently redistribute all properties in excess of 125 acres (51 ha) in addition to all the property of traitors, absentees, and all who collaborated with the wartime Romanian government, the Hungarian occupiers during Miklós Horthy and Ferenc Szálasi's régimes, and Nazi Germany.

[17] Despite giving the appearance of liberal democracy by granting women's suffrage, Groza pursued a series of reforms attempting to clamp down on the prominence of politically dissident media outlets in the nation.

Although Groza had promised to purge only individuals from the government bureaucracy and diplomatic corps immediately after assuming power, in June 1947 he began to prosecute entire political organizations, as, after the Tămădău Affair, he arrested key members of the National Peasants' Party and sentenced Maniu to life in prison "for political crimes against the Romanian people".

[8] On August 18, Roy Melbourne presented to Foreign Minister Gheorghe Tătărescu a verbal note showing that the American government "wants the establishment of a representative regime made up of all democratic groups in this country".

Faced with Groza's refusal to resign, King Michael instituted, on August 21, the royal strike and no longer agreed to countersign the government's documents.

At the December 1945 Conference, it was decided that the situation should be resolved by appointing one PNL and PNȚ member each to the government, after which free elections would be organized and freedom of "press, speech, religion and association" would be ensured.

Basically, the decisions in Moscow represented the victory of the Soviet point of view, the government of Petru Groza being recognized by the USA and Great Britain on February 5, 1946.

[19] Early on the morning of 30 December 1947, Groza summoned Michael back to Bucharest, ostensibly "to discuss important matters"; the king had been preparing for a New Year's party at Peleș Castle in Sinaia.

Instead, the governing parties claimed that the election results reflected the citizens' adherence to the BND program, and the minor incidents that occurred were provoked by the opposition.

The memoirs prepared by Maniu and Brătianu were not taken into account, and on December 1, 1946, King Michael delivered the Opening Message of the Assembly of Deputies: "I am happy to be among the representatives of the country, gathered today for the first time, after a long interruption of parliamentary life."

On February 10, 1947, Romania signed the Peace Treaty with the Allied and Associated Powers, so the regime of the Armistice Convention officially ended.

This fact meant that the UK and the United States no longer had any leverage to intervene in favor of the opposition, Romania passing under the exclusive control of the USSR.

After the parliamentary elections, the essential political objective of the Groza government was to seize all power in the state and liquidate any forms of opposition.

On July 14, 1947, the Home Office authorities managed to set a trap for the main peasant-national leaders, who were preparing to leave for Great Britain to inform Western diplomats about the real situation in the country.

In order to allow the involvement of PNȚ and Iuliu Maniu, the authorities extended the charges from fraudulent attempt to leave the country to activities of a political nature.

The diary stated: "The National-Peasant Party under the presidency of Mr. Iuliu Maniu is and remains dissolved on the date of publication in the Official Monitor of this Journal.

On November 12, King Michael and Queen Mother Elena went to London to witness the marriage of Princess Elizabeth, the heir to the British Crown.

On Christmas Eve, Emil Bodnăraș (who, according to some information, had just arrived from Moscow, where he had received from Stalin the instructions regarding the organization of the abdication of King Michael), was inaugurated as Minister of National Defense.

In a report from December 1990, Michael claimed that Groza and Gheorghiu-Dej resorted to blackmail: "They told me that the members of the government, that is, the communists, would have to, in order to counteract any form of opposition, execute over a thousand of students among those who had been arrested in the last year".

The first took note of the abdication of King Michael I, for himself and his descendants, the Constitution of Romania was abrogated, and the new official name of the state became the Romanian People's Republic.

Ten days later he replaced Constantin Ion Parhon as president of the presidium of the Great National Assembly, the institution that symbolically ensured the leadership of the RPR.

He was then named president of the Presidium of the Great National Assembly (de jure head of state of Romania), a post he held until 1958, when he died from complications following a stomach operation.