Complex sentence: The neo-classical Brandenburg Gate was completed in the early 1790s by Carl Gotthard Langhans; and the copper quadriga by Johann Gottfried Schadow was placed on it in 1793.
Split into simpler sentences: The neo-classical Brandenburg Gate was completed in the early 1790s by Carl Gotthard Langhans. The copper quadriga by Johann Gottfried Schadow was placed on it in 1793.