Serbia is located on the Orthodox side of the Orthodox/Roman Catholic divide across Europe, and for centuries was involved in the conflict between Christians and Muslims in the Balkans. It has been no stranger to religious wars.
Serbia used to be part of Former Yugoslavia.
Language and culture
The official language of Serbia is Serbian, which is Serbo-Croat written in the Cyrillic alphabet; however, different regions develop different customs, languages and the like... Other languages spoken include Albanian, Slovak and Romanian. Historically most Serbs have been Orthodox Christians. Serbo-Croat speakers who are Muslim tend to consider themselves Bosniaks and those who are Catholic are Croats.
World War I was started by a group of Serbian freedom fighters/nationalists when they murdered the heir to the throne of the Austro-Hungarian Empire.  Serbia went on to lose a higher proportion of its population in the First world War than any other combatant, but they did emerge as Yugoslavia, united with their newly "liberated" fellow Serbo-Croats and other South Slavs of the Austro Hungarian Empire.
During the 1990's Serbia was involved in devastating wars with other lands in Former Yugoslavia, as everyone but the Serbs chose to secede from it.