How were the major empires (Austro-Hungarian, German, Russian, and Ottoman) involved, and how did that involvement transform ancient local hostilities into a global conflict of unimaginable proportions?

What were the major issues that caused the various Balkan peoples to wage war against each other in 1912-13? Be sure to identify the contenders involved in each. How were the major empires (Austro-Hungarian, German, Russian, and Ottoman) involved, and how did that involvement transform ancient local hostilities into a global conflict of unimaginable proportions?