With eyes fixed on a Peruvian campaign it was only natural that San Martin should leave immediate details in Chile to others. Though all central Chile submitted with good grace, the South remained a stronghold of the Spanish sympathisers. Among its warlike people the royalist armies had been recruited, and there lay the two strongest fortresses--Talcahuano and Valdivia--both of them still in possession of the Spaniards. After two months' delay, Las Heras, with a thousand men, was despatched, but his force was inadequate and his advance slow. Before he arrived near Concepcion, an able Spanish general, Ordonez, who had fought side by side with San Martin in Spain, had organised a division equal in numbers, with which he retired to Concepcion and there was joined by the sixteen hundred troops who had escaped after the rout at Chacabuco, and who had been ordered back to Chile the moment they made their appearance at Callao. The Spanish general now thought himself strong enough to annihilate Las Heras, but the sortie which he led was beaten back in the battle of Gavilan. However, this victory was in no way decisive, and the patriots were not able to make any impression on the fortifications at Talcahuano or to advance south of the Biobio. Southern Chile remained hostile and Talcahuano and Valdivia were open doors through which the Spaniards could send reinforcements and supplies as long as they held command of the sea. San Martin remained in Santiago only a short time after Chacabuco. Prepossessed with the idea that Chile could never be safe or Peru won until he had organised a fleet to wrest control of the Pacific from the Spaniards, he hastened across the Andes to arrange with his friends in the Argentine government for the necessary money. The Chilean campaign had saved Buenos Aires from impending invasion; the Argentine patriots would certainly be crushed if Chile should fall back into Spanish hands; they could never feel secure so long as Peru and Bolivia remained royalist. The promises which he asked were readily given, on his agreeing that Chile should contribute three hundred thousand dollars toward the purchase of a squadron on the Pacific, and forty thousand for the support of the Argentine army on the Bolivian frontier, besides taking the responsibility of the pay and maintenance of the Army of the Andes. Argentina was to aid in purchasing the fleet and hold back the Spaniards on the Bolivian border.