Complex sentence: John Jacob Astor was born in Walldorf, near Heidelberg in the old Palatinate which became part of the Duchy of Baden in 1803 (now in Rhein-Neckar-Kreis in the state of Baden-Württemberg, Germany).
Split into simpler sentences: John Jacob Astor was born in Walldorf, near Heidelberg in the old Palatinate. It became part of the Duchy of Baden in 1803 (now in Rhein-Neckar-Kreis in the state of Baden-Württemberg, Germany).