Early Life and Formation
Petar Petrović was born in 1748 in Njeguši, in the Prince-Bishopric of Montenegro, to Marko Petrović and Anđelija Martinović. Following the path of his relatives in the ruling Petrović family, he entered monastic life, becoming a monk and a deacon. By tradition he was tonsured and ordained to the diaconate when he was only seventeen.
From 1765 to 1769 he spent four years in Imperial Russia, where he completed military school training before returning to take up ecclesiastical office.
Consecration and Rule
On 13 October 1784 he was ordained bishop by Mojsije Putnik of the Metropolitanate of Karlovci at Sremski Karlovci. He afterward traveled to Vienna, where he met the Russian chancellor Potemkin and Austrian officials, before being expelled from St. Petersburg in November 1785.
He served as Prince-Bishop, or Metropolitan, of Montenegro from 1784 to 1830, succeeding Arsenije Plamenac and preceding Petar II Petrović-Njegoš. He shared leadership with the guvernadur Jovan Radonjić, which produced tension between Russophile and Austrophile factions within the Montenegrin state.
Governance and Reform
Petar I's major legislative achievement was the introduction of the first laws in Montenegro in 1798, which sought to modernize governance through taxation, schools, and commercial enterprises.
He worked to unify the warring Montenegrin tribes, including the resolution in 1797 of a thirty-two-year blood feud between the Njeguši and Ceklin tribes.
Wars and Defense of Montenegro
Petar I led Montenegrin forces against Ottoman expansion. At the Battle of Martinići and the Battle of Krusi on 22 September 1796, Kara Mahmud Pasha was defeated and killed; a Montenegrin force of roughly 6,000 reportedly faced an Ottoman army said to number 30,000 and including seven French officers. The victory enabled territorial expansion, with the tribes of Bjelopavlići and Piperi joining the Montenegrin state.
During the Napoleonic Wars of 1806–1807 he led Montenegrin forces against French troops advancing toward the Bay of Kotor, cooperating with the Russian admiral Dmitry Senyavin. In 1807 he conceived a pan-Serbian plan to revive a 'Slaveno-Serb empire' uniting surrounding territories under Russian protection, a design thwarted by the Treaty of Tilsit. He also cooperated with the Serbian rebel leader Karađorđe during the First Serbian Uprising.
Canonization and Legacy
Petar I died on 31 October 1830 in Cetinje, aged eighty-one or eighty-two. He was canonized as Saint Peter of Cetinje by his successor, Petar II Petrović-Njegoš, approximately four years after his death, in October 1834, on the fourth anniversary of his repose. Most Montenegrins received the canonization with great enthusiasm, and many flocked to his tomb in Cetinje to celebrate the event.
The Serbian Orthodox Church commemorates him on October 31 in the Gregorian calendar, corresponding to October 18 in the Julian calendar.
Relics & Shrines
Cetinje Monastery houses the relics of Saint Peter of Cetinje together with his bishop's crown. His mortal remains are kept there as an object of veneration, alongside other significant relics held by the monastery, including the right hand of John the Baptist and particles of the True Cross.