 On August 4, 1821, insurgent Celestino Negrete began the siege of the city of Durango, which was defended by the governor intendant Diego García Conde and marshal José de la Cruz, ending with their decision on September 6.On August 14, 1821 the Iturbidist Gaspar Antonio López took over as Captain general of the Eastern Internal Provinces in Monterrey.While, in the Western Internal Provinces Captain General Alejo García Conde pact with Negrete and joined the Plan of Iguala proclaimed by Agustín de Iturbide, making him swear it in Chihuahua on August 26 and then in Arizpe on September, 6.