Danilo I Petrovic-Njegoš (Serbian Cyrillic: ?????? I ????????-?????; 25 May 1826 – 13 August 1860), was ruling Prince of Montenegro, from 1851 to 1860.
Beginning of his reign marked the transition of Montenegro from an archaic form of government (Prince-Bishopric) into a secular Principality.He became involved in a war with the Ottoman Empire in 1852, the Porte claiming jurisdiction in Montenegro, and the boundaries between the two countries were not defined until 1858.
Danilo, with the help of his elder brother, Voivode Mirko, defeated the Ottomans at Ostrog in 1853 and in the Battle of Grahovac in 1858.