Complex sentence: Athalaric (516-2 October 534), King of the Ostrogoths in Italy, grandson of Theodoric the Great, became king upon his grandfather's death in 526.
Split into simpler sentences: Athalaric (516-2 October 534) was the King of the Ostrogoths in Italy. The grandson of Theodoric the Great, he became king upon his grandfather's death in 526.