There are dozens of economic simulation games on the A8 (Kingdom, Safryland, Kaiser, Kaiser 2, Fuerstentum, Oilwell, Oel Imperium, etc.) and even this game is available in two or three different versions. After playing approx. 10-12 different economic games, I can say that Santa Paravia is a very good and fair game.
It is easy to understand, does not need any manual and has adequate (mostly text) graphics. Today I played the game twice and ended as King in both sessions. So, if you search for a Kingdom type game in the public domain, this one is it.