Complex sentence: Christian IV's expeditions in the years 1605-1607 to Greenland and Arctic waterways were sent by King Christian IV of Denmark in order to locate the lost Eastern Norse Settlement and reassert Danish sovereignty over Greenland.
Split into simpler sentences: Christian IV's expeditions were sent by King Christian IV of Denmark to Greenland and Arctic waterways during the years 1605-1607. The expeditions were commissioned in order to locate the lost Eastern Norse Settlement and reassert Danish sovereignty over Greenland.