Bolívar and Brión returned and tried in 1817 to capture Barcelona, where the Spaniards repulsed them. In the meantime, Piar and Mariño had occupied defenceless Angostura (a city at the narrowest and deepest part of the Orinoco River, hence its name, subsequently changed to Ciudad Bolívar), to where Bolívar headed and was chosen as supreme leader of the independence movement. (It was at this time that Bolívar ordered the addition of a new star for Guayana to the seven stars on the Venezuelan flag, which represented the number of provinces that originally had favored independence. Since Bolívar played a central role in the symbolism of the Venezuelan government led by Chávez, this long-forgotten change was revived in the 2006 revision to the flag.) Once in Guayana, Bolívar quickly cashiered Piar, who had been trying (or was accused of trying—historians still debate this) to form a "pardo" force of his own, by having him arrested and executed after a court martial in which Brión was one of the judges. British veterans of the Napoleonic wars began arriving in Venezuela, where they formed the nucleus of what later became known as the British Legion. Morillo returned to Caracas and Morales was given troops to dominate eastern Venezuela, which he did successfully. Francisco de Paula Santander, a New Granadan who had retreated to the llanos after Morillo's invasion, met with Bolívar and agreed to join forces. Morillo's other lieutenant, the second in command of the expeditionary force, Miguel de la Torre, was ordered to put down a significant rebellion in the llanos of Apure led by José Antonio Páez. At the time in the Southern Cone of South America, José de San Martín had concluded the liberation of Chile with the essential support of the Chilean Bernardo O'Higgins.