The Balkan Peninsula is commonly brought up when discussing regions that have a history of violence, was it always like this or is this a relatively (~100 years) new?
I feel like a good amount of people are aware of the modern issues occurring- pre-cursor to WWI, general unrest- but otherwise don't realize the depth of issues occurring in the area.
From my limited knowledge, the fall of the Ottoman Empire was a major factor in the disfunction of the area in the early 20th century.
I did my undergrad in History and was always fascinated by the politics of Eastern Europe due to cultural heritage (Polish and Czech blood) but my University had limited classes available.
Please let me know if this breaks any sort of rules so I can try to fix it!
Edit: Armenian genocide is not a part of the Balkan Peninsula but the area was under Ottoman control, hence my inaccurate association of the two.
This isn't an area that I have studied very much at all, but one of the books that I'm currently reading is Robert Kaplan's The Revenge of Geography (he is far more of a pop-historian/polisci type guy than a real historian). He points out early on in the book that the Balkans served as the frontier zone between the Austro-Hungarian Empire and the Ottoman Empire.
Numerous different groups of people were slowly forced into this area as the two empires expanded, leading to the current hodge podge of different ethnic and religious groups in the area.
Additionally, it is largely a very mountainous area, which Kaplan argues made it difficult for either of the two big empires to really exert effective control over the area, even when parts of the Balkans were under the nominal control of either empire.
Combined, you have a bunch of different ethnic and religious groups, speaking a bunch of different languages, with a tradition of semi-autonomy, that were then more or less put into different countries. This is a common source of conflict, especially when the governments are dominated by specific religions/ethic groups, and the minority groups are underrepresented.
Better question is was there really an extensive history of violence?
Let's skip medieval period and start with Ottoman wars which were like 30 years war, a long conflict that went on and off for a long time. A lot of such wars in the period, or generally wars.
Balkans also had revolutions of 19th century, like the rest of Europe. Then two Balkan wars which gave it the name of powderkeg of Europe, which simply happened when Europe was at peace, at least at home, in preperation of the Great War, but Europeans were quite active in the colonies, though those wars were far away and insignificant natives were getting hurt, far from eyes and far from heart as we say. Then there were two World wars, again shared by whole Europe (also Balkans missed a few like winter war, Polish-Soviet war and Spanish civil war, and then Korea, Vietnam and more colonial conflicts), and then we had 1990's, again in era of European peace but at the same time as several other post-Communism wars and at the same time as Europeans were again fighting across the World (Falklands, Gulf war).
I would hardly call wars fought in Balkans any bloodier than wars fought elsewhere. Wars for territory are the same everywhere. One of defining things in such wars, specially when there is a claim based on demographics, is to purify the area of undesireable demographics, usually through eviction (which is called ethnic cleansing when it's done in Balkans) or forced assimilation. The difference is Balkan countries, being small and weak and easily influenced by powers, are never allowed to finish their wars with complete victory so the same wars repeat.
Another question that is related to this, to what extent did the emergence of national consciousness/nationalism in the 19th century cause the downfall of the Ottoman Empire in its European territories?
also OP neither Poland, nor the Czech lands, nor Armenia are situated in the Balkans.