He was believed to have died in the Eighty Years ' War in the Netherlands .
His father , Heinrich Kepler , earned a precarious living as a mercenary , and he left the family when Johannes was five years old .
Johannes was believed to have died in the Eighty Years ' War in the Netherlands .
His father , Heinrich Kepler , earned a precarious living as a mercenary , and he left the family when Johannes was five years old .