The Role of the Balkan Countries in WWI
One of the reasons there was so much tension in the Balkans before the outbreak of World War 1, was that the Balkans was the connection between Germany and her allies with the Ottoman Empire and the Persian Gulf. The following map shows the Balkans before the Balkan Wars of 1912-1913.
The Balkans Before the Balkan Wars of 1912-1913
It can be seen on the above map, that with the status quo that existed before the Balkan Wars of 1912
and 1913, Germany would have no problem to connect to the Persian Gulf by railway, using the Austro-Hungary-Ottoman Empire corridor.
However with the Balkan Wars of 1912-1913, Greece, Serbia, Bulgaria and Albania, managed to annex almost all the European territories of the Ottoman Empire. Greece, Serbia and Romania, all of which were on the side of the allies during the First World War, formed a wall between Germany and the Ottoman Empire as you can see on the following map, (Bulgaria finally entered the war on Germany"s side in WWI).
The Balkans after the Balkan Wars of 1912-1913
The German plan was to construct the famous Baghdad Railway, that would connect Berlin to the Persian Gulf (see later sections), and Greece, Serbia and Romania were forming a wall against the Baghdad Railway Project. It is not a coincidence that World War I broke out on the 28th of July 1914, with the Austro-Hungary declaring war to Serbia, with all other countries running behind these two countries. The following map shows the Balkans today.
It can also not be a coincidence that the Balkan Wars took place in 1912 and 1913, and the First World War broke out in 1914. When I am saying that the Balkan Wars were not a coincidence, I do not mean that Greece, Serbia and Bulgaria attacked the Ottoman Empire because they wanted to prevent Germany from connecting to the Persian Gulf. These countries did want the Ottoman territories, and they were supported by England, Russia and France, in order to prevent the German-Ottoman connection. The Ottoman territories were simply their rewards.
As you can read in section "Reaction Among the Great Powers During the Wars" of the following Wikipedia link, Germany was already heavily involved in the internal politics of the Ottoman Empire, and officially opposed the attack on the Ottoman Empire, but because it was obvious that the shaky Ottoman Empire could not protect for long her European territories from Greece, Bulgaria and Serbia, Germany was supporting Bulgaria from the opposite camp, which was called the "Balkan League"".
And in the end, Bulgaria did indeed join Germany"s camp in WW1.
https://en.wikipedia.org/wiki/Balkan_Wars#Reactions_among_the_Great_Powers_during_the_wars
In the same Wikipedia link, you can also read that Russia was the primary mover of the Balkan League countries i.e. Greece, Serbia and Bulgaria against the Ottoman Empire. This seems very natural, since Russia not only wanted to prevent Germany from obtaining access to the Caspian Sea, but she was also a traditional enemy of the Ottoman Empire and wanted to gain control of Constantinople, Bosphorus and the Dardanells, which would allow the Russian Navy to access the Mediterranean Sea, as I already said.
You can also read in the same Wikipedia link that Austria-Hungary was totally opposed to the advancement of the Balkan countries, Greece, Serbia and Bulgaria, in the region. France, a Russian ally, informed Russia that she was not ready for a war. England, even though a supporter of the Ottoman Empire, encouraged the advancement of the Balkan countries. That"s what Wikipedia says about the reactions of the Great Powers during the Balkan Wars of 1912 and 1913.
We therefore see that Germany and Russia were supporting the sides we would expect them to support in the Balkan Wars. However things were a bit more complicated for England. Because on one hand England was facing the threat of German expansion to the Persian Gulf and India, and on the other hand she was facing the threat of Russian expansion through the Straits of Bosphorus and the Dardanelles to the Mediterranean Sea, which could pose a threat for the sea corridor between the Mediterranean Sea and the Indian Ocean i.e. the Suez Canal and the Red Sea.
The following map depicts the situation for the English. The purple arrows represent the German threat to the Persian Gulf and India, and the red arrows represent the Russian threat to the Suez Canal.
The German threat for the English (purple lines), and the Russian threat for the English (red lines)
England perceived the collapsing Ottoman Empire as less dangerous than the Russian Navy for the control of the Suez Canal and Egypt. However in the end, under the German threat for the Persian Gulf and India, England accepted Russian control over the straits of Bosphorous and the Dardanelles in case of victory. With the Constantinople Agreement as I already said, France, England and Russia agreed on the control of Constantinople and the Straits by Russia.
Another factor that helped England and Russia to reach an agreement was that around 1880, England had taken control of Cyprus, Egypt and the Suez Canal, and was feeling more confident that it could prevent the Russians from taking control of the Suez Canal.
Before I close the section on the Balkans, I must mention that the "wall" formed by Greece and Serbia in 1914 against Germany and the Baghdad Railway, which prevented the Germans from connecting by railway to the Ottoman Empire and the Persian Gulf, was still there 80 years later. Greece and Serbia, two traditional Russian allies, were forming a wall in the 90"s against the Americans and the Europeans, who wanted to bring oil and natural gas from Azerbaijan to the Adriatic Sea and Italy through the AMBO pipeline.
The Greek-Serbian wall was broken first by the creation of the state of FYROM (Former Yugoslav Republic of Macedonia) in 1991, and by the NATO war on Serbia and the autonomy of Kosovo in South Serbia on 1998 (see following map). You can read more about the NATO attack on Serbia and the AMBO pipeline in my essay "The NATO attack in Yugoslavia – Another Energy War".
