"Peter I (Serbian: Petar/Петар; 11 July [O.S. 29 June] 1844 – 16 August 1921) reigned as the last King of Serbia (1903–1918) and as the first King of the ...
Serbs, Croats and Slovenes (1918–1921). Since he was the king of Serbia during a period of great Serbian military success, he was remembered by Serbian people as King Peter the Liberator, and also known as Old King.
Peter was Karađorđe´s grandson and third son of Persida Nenadović and Prince Alexander Karađorđević, who was forced to abdicate. Peter lived with his family in exile. He fought with the French Foreign Legion in the Franco-Prussian War. He joined as volunteer under the alias Peter Mrkonjić in the Herzegovina Uprising (1875–77) against the Ottoman Empire." - (en.wikipedia.org 31.01.2020)
