Complex sentence: When his grandfather Valdemar IV of Denmark died, Oluf was, just five years old, proclaimed King of Denmark by a Danehof in Slagelse the following year while his mother, Queen Margaret, was to serve as regent due to his young age.
Split into simpler sentences: When his grandfather Valdemar IV of Denmark died, Oluf was just five years old. His mother, Queen Margaret, was to serve as regent due to his young age.