Every setting has different sources of inspiration, often quite odd sources at that. In the case of Tòlanar, the inspiration was the rather cheesy TV series Reign. I was watching it and thinking about a discussion on Birthright.net about making the game more appealing to women by having more female regents and I thought that the whole Mary Queen of Scots storyline would be a good one for that purpose, so I set about looking at my various maps for a good place to put that scenario and I found it on the Tollanar map I made.
Once I had settled on that map, I started thinking about how to set it up. I decided that I wanted a highly feudalized setting, with various nobles owning patches of land scattered around the country rather than geographically contiguous ones that are so common, so I started reading up on the various counties, etc. in Medieval Europe for some ideas and I came across a massive listing of all the states in the Holy Roman Empire. I started fooling around with those a bit and quickly realized that if I were to use that as a template it would need LOTS of provinces, so I decided to use that template for the lands beyond the mountains in the upper section of the map to the left.
From there I just used Wikipedia to get my ideas. For example, the Greece section I decided to use the Byzantiner Empire as my inspiration rather than the more familiar Classical era.
Once I had decided on the European template, I adapted European history as well, to get an idea of the past empires, etc. which would give me a rough boilerplate for cultures, cultural influences, languages, and so on.
Some aspects of the resulting setting are very direct takes from European history, and others are very loosely adapted. I found this approach useful as it gave some coherence and believability to the various nations.
It also allowed me to create some interesting subdivisions of the various nations, ranging from the chaotic mish-mash of scattered holdings in the areas based on western Europe to the highly structured one in the Greco-Byzantine based areas.