Complex sentence: It was first constructed for Cornelius Vanderbilt II in 1883, the ground level containing a drawing room, dining room (which doubled as the art gallery), reception room and stables in the back.
Split into simpler sentences: It was first constructed for Cornelius Vanderbilt II in 1883. On the ground level was a drawing room, a dining room (which doubled as the art gallery), and a reception room, with stables in the back.