The Spaniards had about 13,000 men guarding the rather antiquated fortifications of old Manila and a semicircle of blockhouses and trenches thrown about the city, which contained about 350,000 inhabitants.
It would have been easy to compel surrender or evacuation by the guns of the fleet, had it not been for an additional element in the situation.
Manila was already besieged, or rather blockaded, on the land side, by an army of nearly ten thousand Philippine insurgents under their shrewd leader, Emilio Aguinaldo.

It does not necessarily follow that those who are fighting the same enemy are fighting together, and in this case the relations between the Americans and the insurgents were far from intimate, though Dewey had kept the situation admirably in hand until the arrival of the American troops.
General Merritt decided to hold no direct communication with Aguinaldo until the Americans were in possession of the city, but landed his army to the south of Manila beyond the trenches of the Filipinos.

On the 30th of July, General F.V.Greene made an informal arrangement with the Filipino general for the removal of the insurgents from the trenches directly in front of the American forces, and immediately advanced beyond their original position.

The situation of Manila was indeed desperate and clearly demanded a surrender to the American forces, who might be relied upon to preserve order and protect property.

The Belgian Consul, M.Eduard Andre, urged this course upon the Spanish commander.
The Governor-General, Fermin Jaudenes, exhibited the same spirit which the Spanish commanders revealed throughout the war: though constitutionally indisposed to take any bold action, he nevertheless considered it a point of honor not to recognize the inevitable.