The English, under Admiral Edward Vernon, had created havoc in the Spanish trade with the Indies, taking Portobelo, Panama in 1739, and laying siege to Cartagena (Colombia), which they did not succeed in taking. Fearing that Veracruz was next, Castro y Figueroa ordered construction of new batteries at San Juan de Ulúa, more supplies, the drafting of a militia, and the raising of a battalion of marines named "La Corona". He went personally to Veracruz to supervise the new measures, but he soon came down with hemorrhagic dysentery. He was transported back to Mexico City, where he died August 22, 1741.