Final answer:
Robert Stewart warned against restoring authority to royalty at the Congress of Vienna.
Step-by-step explanation:
At the Congress of Vienna, Robert Stewart, also known as Lord Castlereagh, cautioned against restoring authority to royalty. He believed that the focus should be on maintaining a balance of power and preventing any one nation from becoming too dominant. Stewart's warning was motivated by the desire to avoid future conflicts and establish a stable post-Napoleonic European order.
Learn more about Congress of Vienna