Complex sentence: Lucius Verus (15 December 130--169) was the co-emperor of Rome with his adoptive brother Marcus Aurelius from 161 until his own death in 169.
Split into simpler sentences: Lucius Verus (15 December 130--169) was the co-emperor of Rome with Marcus Aurelius from 161 to 169. He ruled together with his adoptive brother Marcus Aurelius as co-emperor from 161 until his own death in 169.