The Elector invaded Schwarzburg and torched the city of Sondershausen .
In feudal matters , he came into conflict with Elector Johann Frederick I , Elector of Saxony .
The Johann Frederick I , Elector of Saxony invaded Schwarzburg and torched the city of Sondershausen .
In feudal matters , he came into conflict with Elector Johann Frederick I , Elector of Saxony .