His tenure of the foreign office was coincident with a very critical period in international relations. But for the sympathy of Britain under Palmerston, the July Monarchy would have been completely isolated in Europe, and this sympathy the aggressive policy of France in Belgium and on the Mediterranean coast of Africa had been in danger of alienating. The Belgian crisis had been settled, so far as the two powers were concerned, before De Broglie took office, but the concerted military and naval action for the coercion of the Dutch, which led to the French occupation of Antwerp, was carried out under his auspices. The good understanding of which this was the symbol characterized also the relations of De Broglie and Palmerston during the crisis of the first war of Muhammad Ali with the Porte, and in the affairs of the Spanish peninsula their common sympathy with constitutional liberty led to an agreement for common action, which took shape in the Quadruple Alliance between Britain, France, Spain and Portugal, signed at London on 22 April 1834. De Broglie had retired from office in the March preceding, and did not return to power until March of the following year, when he became head of the cabinet.