Complex sentence: Before he died in 1856, he divided his family possessions--granddaughter Helena obtained Veveří Castle, but at that time she was still a juvenile, so the property was administered by her father.
Split into simpler sentences: Before he died in 1856, he divided his family possessions. His granddaughter Helena obtained Veveří Castle, but at that time she was still a juvenile, so the property was administered by her father.