Nistor was born into a family of peasants in the Bivolărie hamlet of
Vicovul de Sus, Bukovina — in
Austria-Hungary at the time, it is now included in
Suceava County, Romania. He studied at the local school in Vicovul de Sus, then at Elementary School of
Rădăuţi and at the Rădăuţi
German High School, getting his
Matura in 1897.
He then studied Philosophy and Literature at the
University of Czernowitz and between 1898 and 1900, he completed his military service in the
Austro-Hungarian Army (serving in
Polei and in
Vienna), and graduated from the University in 1902, after which he was named teacher of history and geography at the Suceava Classic High school. Together with some of his friends, Nistor edited a magazine titled
Junimea Literară between 1904 and 1914, first published in Rădăuţi and then in Suceava.
In 1904, Nistor married Virginia Puliuc, daughter of the Gheorghe Pauliuc (a
Romanian Orthodox priest from
Burla), and, one year later, on
July 5 1905, Oltea, his only child, was born. He then moved to teach at the Orthodox High School, making use of the institution's library, better suited to his studies into the history of
Moldavia.
In 1908-1909 and 1910-1911, he studied at the
University of Vienna and completed his
PhD under
Konstantin Josef Jireček, with a thesis on
Moldavia's aspirations regarding Pokuttya. After that, he furthered his studies at the Universities of
Munich, Leipzig and
Berlin, receiving (1911) his
Docent title and the
Venia legendi, which allowed him to teach at the University of Vienna, where he gave lectures on the
history of the Romanians.
A year later, in 1912, he moved to Czernowitz, to hold the chair of
Southeastern European history, but after the start of
World War I, he moved to the
Romanian Old Kingdom, where he published various studies on the history of
Bukovina. He was elected a member of the
Romanian Academy in 1915. He also authored an
ethnographic map of Bukovina under
Austrian domination (
see Cisleithania), based on the census of 1910.
Living in
Iaşi by the time Romania entered the war on the
Entente side, Nistor left Romania at the climax of the
Romanian Campaign (when troops of the
Central Powers threatened the region). In July 1917, he moved to
Odessa, in territory held by the
Russian Provisional Government, and began teaching Romanian history to the (mostly
Bessarabian) students at the
University of Novorossiya. He interrupted the course in November 1917, after a group of armed
Russian revolutionaries broke into the University building. Nistor was, however, safely escorted outside by some of the Bessarabian soldiers who were part of his audience.
In February 1918, together with other Austro-Hungarian refugees (including
Octavian Goga), Nistor departed for
Ovidiopol, Cetatea Albă and then finally reached
Chişinău. He stayed in the city, where he argued for the founding of a Moldavian University, and soon began lecturing on the History of the Romanians. He used the data gathered from the Chişinău Archives to write the
History of Bessarabia, published in 1923. Nistor also witnessed the
Sfatul Ţării session which voted the union with Romania.
After the war ended, he returned to his native Bukovina and he was one of the members of the National Assembly of Bukovina in
Cernăuţi, which voted for the
union with Romania on
November 28, 1918. Nistor was also one of the fifteen Bukovinans who presented the Union Act to Romania's
King Ferdinand I.
Between December 18 and May 2, Nistor was a member of
Greater Romania's Ion I. C. Brătianu government, as a Minister for Bukovina, and, between February 14 and February 27, also held the rank of minister for Bessarabia, while the nominal minister was delegated to the
Paris Peace Conference. Between May 1920 and January 1922, Nistor was a
Senator in the
Parliament of Romania.
In the
interwar period, Nistor wrote many historical works, including
The Origin of Romanians and the Vlachs of Thessalia and Epirus and
The History of Romanians in Transnistria (1925). He was also the director of the historical magazine
Codrii Cosminului, which was published between 1924 and 1939.
Elected
rector of the
University of Cernăuţi in 1920, at the same time when he joined the
National Liberal Party (PNL), Nistor was again the Minister of State for Bukovina in the fourth Brătianu cabinet (1922-1926), Minister of Public Works in the fifth Brătianu cabinet (1927-1928), and Minister of Labour in the first
Gheorghe Tătărescu cabinet (1934). In 1938, he broke with the PNL and sided with the
National Renaissance Front regime established by King
Carol II, and was Minister of the Cults and Arts in the second Tătărescu cabinet (
November 24, 1939–May 12, 1940).
Starting October 1940, under the
National Legionary State, Nistor taught at the
University of Bucharest, becoming the target of
Iron Guard persecutions for the support he had given to King Carol. Following the Guard's defeat during the
Legionnaires' Rebellion of 1941, he sent a congratulatory telegram to
Conducător Ion Antonescu. He was pensioned in the same year, and, starting 1943, he was in charge of Library of the
Romanian Academy. Nistor kept the latter office until after the establishment of a
Communist regime, when the purge of
anti-communists in the Academy began (1948).
His house was
nationalized, and Nistor had to live in the attic of his daughter's house (which was also nationalized). On the night of
May 5/6, 1950, Nistor was arrested for political reasons by the
Securitate, being incarcerated in
Sighet prison. Originally sentenced to 24 months in prison, his sentence was subsequently raised to 60 months.
He was freed five years and two months later. After that, he continued writing, completing his works,
History of Bukovina and
The History of Romanians.