ESLABA, Sebastian (eslah'bah), Spanish soldier, born in Eguiller, Spain, in February 1698; died in Madrid in January 1759. In 1723 he served with distinction as captain of the Spanish guards, and as colonel of the regiments of " Asturias" and "Castilla" he took part in nearly all the battles of the second reign of Philip V., reaching the rank of lieutenant general in 1738. At the beginning of the war between England and Spain in 1740, Eslaba was appointed viceroy of New Granada, and immediately after his arrival set to work to repair the old fortifications of Carthagena and Portobello, and to build new ones. Early in November the most powerful British fleet that had ever been sent to South America appeared before Carthagena, under command of Sir Edward Vernon, and on 5 November the bombardment began.

Notwithstanding that Sir Edward made continuous attacks by land and sea on Carthagena during the prolonged siege, the splendid fortifications withstood the bombardment, and repeated assaults were repulsed by Eslaba, till, in May 1741, the British were forced to raise the siege with the loss of seventeen ships. As a recompense for his services, Eslaba was promoted captain general of the army, and in 1743 was made viceroy of Peru, but did not go to fill this place, as He was called to Spain early in 1744 to become minister of war, and held the office for several years. The splendid fortifications of Carthagena, built under his personal inspection, exist to this day nearly intact. After his death, in 1760, Charles III., in memory of his brilliant defense of Carthagena, raised his son, Colonel Gaspar Eslaba, to the peerage of Castilla, under the title of "Marquis of the Royal Defence."