In Rafter's view, this marked "the zenith of MacGregor's celebrity" in South America. He had, according to his biographer Frank Griffith Dawson, "led his troops with brilliant success"; Sinclair agrees, calling the march a "remarkable feat" demonstrating "genuine military skill". With Bolívar back in Aux Cayes, overall command of the republican armies in Venezuela had been given to Piar. On 26 September, Piar and MacGregor defeated the Spanish army commanded by Francisco Tomás Morales at El Juncal. But MacGregor and Piar had several disagreements over the strategic conduct of the war—according to the American historian David Bushnell, the Scottish general probably "r afoul of personal and factional rivalries within the patriot camp". In early October 1816 MacGregor left with Josefa for Margarita Island, about off eastern Venezuela, where he hoped to enter the service of General Juan Bautista Arismendi. Soon afterwards he received an acclamatory letter from Bolívar: "The retreat which you had the honour to conduct is in my opinion superior to the conquest of an empire ... Please accept my congratulations for the prodigious services you have rendered my country". MacGregor's march to Barcelona would remain prominent in the South American revolutionary narrative for years. The retreat also earned him the title of "Xenophon of the Americas" ().