Complex sentence: After Harald's death, the unity of the kingdom was not preserved, and for the next century, the kingdom was variously ruled, wholly or in part, by descendants of King Harald or by earls under the suzerainty of Denmark.
Split into simpler sentences: After Harald's death, the unity of the kingdom was not preserved. In following centuries, the kingdom was variously ruled, wholly or in part, by descendants of King Harald or by earls under the suzerainty of Denmark.