Complex sentence: The first was excavated by the Han emperor Wudi in the 1st century BC as part of his Jianzhang Palace ("Jiànzhānggōng"); the second by Taizong of the Tang beside his father's Daming Palace.
Split into simpler sentences: The first was excavated by the Han emperor Wudi in the 1st century BC as part of his Jianzhang Palace ("Jiànzhānggōng"). The second was excavated by Emperor Taizong of the Tang beside his father's Daming Palace.