Complex sentence: Johnston was born at his grandfather's house "Panicello", near Abingdon, Virginia, September 9,1818, as the only child of Dr. John Warfield Johnston and Louisa Smith Bowen.
Split into simpler sentences: Johnston was born in his grandfather's house, "Panicello", near Abingdon, Virginia, on September 9,1818. He was the only child of Dr. John Warfield Johnston and Louisa Smith Bowen.