The Quadruple Alliance was formed by a conference in its capital.
One ruler of this empire voided the third Barrier Treaty to free up navigation in a noncontiguous imperial domain. Its overseas trading company was eliminated as part of a treaty arranged by another country's Lord Chesterfield. After losing the battles of Magenta and Solferino, its diplomats attended the Villafranca conference. One foreign minister of this empire called a conference in Carlsbad which issued decrees against its northern neighbor's student unions. This empire's 1756 shift into an allegiance with France triggered a "diplomatic revolution" before the Seven Years' War. The Quadruple Alliance was formed by a conference in its capital. For 10 points, name this empire served by Prince Metternich, whose diplomats bowed to Joseph II and Maria Theresa.
One ruler of this empire voided the third Barrier Treaty to free up navigation in a noncontiguous imperial domain.
Austrian Empire [or Habsburg empire, or Ã–sterreich; do not accept "Austrio-Hungary" or "Dual Monarchy" at any point; prompt "Holy Roman Empire" until "Magenta" is read]