Danilo I Petrović-Njegoš was the ruling Prince of Montenegro from 1851 to 1860. The beginning of his reign marked the transition of Montenegro from a traditional theocratic form of government (Prince-Bishopric) into a secular Principality.

The Principality of Montenegro was a principality in Southeastern Europe that existed from 13 March 1852 to 28 August 1910. It was then proclaimed a kingdom by Nikola I, who then became King of Montenegro.