So, I’ve just realised that I’m mentioning a lot of countries and places, and you might not fully understand where these all are in relation to each other. So here’s a selection of maps which should hopefully help with understanding the geography, at least at a political level.
First off, here are four maps of Europe at various dates through the 19th Century. All have been excellently produced by Wikipedia user KaterBegemot. All licensed under CC BY 4.0
The next few maps deal specifically with the episodes on the Balkan Wars of 1912-13 (Wiki authors or other source credited in captions).
Next, a map of the component map of the Austrian Empire, courtesy of Wikipedia user Spiridon Ion Cepleanu: