A plan was finally developed for the attack on Santiago. Shafter would send his 1st Division (at the time, brigade and division numbers were not unique outside their parent formation) to attack El Caney while his 2nd Division and the Cavalry Division would attack the heights south of El Caney known as San Juan Hill. Originally, Shafter planned to lead his forces from the front, but he suffered greatly from the tropical heat and was confined to his headquarters far to the rear and out of sight of the fighting. Unable to see the battle firsthand, he never developed a coherent chain of command. Shafter's offensive battle plans were both simplistic and extremely vague. He seemed to be unaware or unconcerned about the mass killing effect of modern military weapons technology possessed by the Spanish. Further, his intelligence-gathering efforts on Spanish troop dispositions and equipment was extremely meager, though he had a number of sources available to him, including reconnaissance reports by Cuban rebel forces as well as espionage obtained from indigenous Cubans.