Complex sentence: In 1609, Rudolf II, Holy Roman Emperor and King of Bohemia (1576--1612), increased Protestant rights: increasingly unfit to govern, other members of the Habsburg dynasty declared his younger brother, Matthias, family head in 1606.
Split into simpler sentences: In 1609, Rudolf II, Holy Roman Emperor and King of Bohemia (1576--1612), increased Protestant rights. He was increasingly viewed as unfit to govern, and other members of the Habsburg dynasty declared his younger brother, Matthias, family head in 1606.