Commodore Stockton now set about to organize his conquest, and first of all he issued a proclamation declaring California a territory of the United States. A tariff of duties was established and collectors were appointed to receive them at the different seaports. A constitution was drawn up and put in operation, in which the powers and duties of the various branches of the government were laid down. Major Frémont was appointed governor of the territory, and directions were given for elections to be held for civil magistrates, the conquered country meanwhile remaining under martial law. It had been the commodore's purpose to enlist a force of volunteers, and taking them to Mexico, to land at Acapulco or some other convenient point, and create a diversion of the Mexican army by an invasion from the west coast, and for this reason he had installed Frémont as governor; but circumstances soon after compelled him to change his plan, which after all was perhaps somewhat visionary. In the month of September, while he was busily occupied in northern California, a rising took place at Los Angeles, under General Flores, and Pico the governor, whom the Americans had released on their parole at the capture of the city. The garrison left by the commodore was driven out and took refuge in San Pedro. Thither Captain Mervine was ordered at once in the "Savannah," and thither the "Congress" shortly followed him. Arriving at San Pedro late in October, the commodore found that Captain Mervine had just been defeated by the enemy, who were then besieging the little town. The naval brigade was again landed, and presently the besieging forces were driven off. From this time till the 1st of January the fleet was occupied with preparations for a second and more serious attack upon Los Angeles. The great advantage of the enemy was in his cavalry. Every Californian was an expert horseman, and the Mexican ponies are trained to the severest work. On the other hand the naval brigade, as might be expected, was badly off in this essential arm of service. Commodore Stockton was a man of bold and original mind, but even his mind did not go to the length of forming a corps of marine cavalry; and besides, there were no horses, for the Mexicans had taken care to strip the country of ponies in the neighborhood of the southern ports. Parties were sent out in all directions to obtain them, but with no success. Finally Major Frémont was conveyed to Monterey with his battalion, with the understanding that he should march south by land as soon as he had completed his preparations; but as he was delayed from one cause or another, and as Monterey was three hundred miles north of Los Angeles, he did not arrive in time to take a part in the attack.