In colonial trade, Cadiz acted as a mere entrepot for the exchange of American bullion for European merchandise. The accession of Philip V under challenge of civil war and foreign invasion enabled his French advisors to lay the foundations of an absolutist state with remarkable rapidity. In the New World the Bourbon state proved remarkably successful both in safeguarding its frontiers and in the exploitation of colonial resources. The revival of Spanish power during the reign of Charles III in large measure derived from the efflorescence in trade with the Indies, and from the increased revenue which it yielded. The centre-piece of the administrative revolution in government was the introduction of intendants, officials who embodied all the executive, interventionist ambitions of the Bourbon state. For the American empire the enforcement of the British blockade offered proof of the inability of Spain to protect the interests of its colonial subjects.