But essentially, as already has been suggested, Taylor's advance rested on the necessity of military defence; and indeed there is reason to consider Scott the prime factor in the business, for the order of January 13 was based upon, and in part verbally reproduced, a "projet" submitted by him, whereas Polk's diary for January 12 and 13 does not even allude to the subject. Now not only were defensive measures called for on general principles, as we have just been informed by the London _Times_, but the Texans actually and urgently needed a sheltering arm. During the latter part of 1845 the chief Mexican engineers drew detailed plans for crossing, not only the Rio Grande, but the Sabine. Merely the refusal of Paredes, growing out of his revolutionary designs, to reinforce the troops on the frontier with 2400 men prevented an attack at this time. Almonte, who had particularly recommended incursions into Texas, held the post of war minister in January, 1846. The Mexican troops were extremely mobile. Ampudia's main force, at the end of a long march, did 180 miles in four days. Screened by rancheros and living on a little corn and jerked beef carried in their pouches, a body of light cavalry could have reached San Antonio by way of Laredo, ruined the town, and been well on their way toward home before their movement would have been suspected at Corpus Christi. The government received warnings of this danger from Dimond and from Parrott in 1845; Marcy and Polk feared it; and the probable rejection of Slidell--which meant a triumph of the war party--seemed likely to accentuate the peril. In fact Mejía ordered irregulars into Texas on February 16 and March 17, though, as their commander aspired to execute a revolution with American aid, he did us no harm.[7.31] Nor were only such formal incursions to be guarded against. The war of 1836 in Texas had shown what outrages Mexicans were capable of committing, and similar affairs had now begun to occur. In one instance a party of fifteen, including women, after having been induced to surrender, were all butchered except a single person, who survived though seriously wounded. In April, 1846, the Mexicans opposite Matamoros confessed that bloodthirsty guerillas were abroad. Ampudia, whose murderous record had been his chief distinction, commanded there. May 13 the British consul in that city reported that licensed bands of assassins, "caressed, rewarded, and encouraged" by the authorities, were committing atrocities near the Rio Grande; and, had the way been open, such gangs might have robbed and murdered in the settlements of Texas.[7.32]