Complex sentence: The history of Hesse began in 1568 with the death of Philip of Hesse, the Landgraviate of Hesse (German: Landgrafschaft Hessen), a German Principality of the Holy Roman Empire, was divided between his sons.
Split into simpler sentences: The history of Hesse began in 1568 with the death of Philip of Hesse, the Landgraviate of Hesse (German: Landgrafschaft Hessen). Hesse was a German Principality of the Holy Roman Empire and upon the death of Philip, it was divided between his sons.