Complex sentence: During her exile, Arsinoe I lived in great splendour and exercised considerable power, although she was a wife of a former Pharaoh and her first son with Ptolemy II, succeeded his father after his death.
Split into simpler sentences: During her exile, Arsinoe I lived in great splendour and exercised considerable power, since she was a wife of a former Pharaoh. Her first son with Ptolemy II succeeded his father after his death.