April 12 General Ampudia, of the Mexican forces at Matamoros, serves notice upon General Taylor either to withdraw within twenty-four hours and return to the Nueces out of the disputed territory, or else accept war. General Taylor replies that his orders are for him to remain here until the boundary dispute is settled. He announced a blockade of the Rio Grande River. April 19 Second Lieutenant Theodoric Henry Porter, Fourth Infantry, is killed in action with Mexican guerillas. April 25, this 1846, occurs the first battle of the war, when at La Rosia a squadron of sixty-three Second Dragoons under Captain Seth B. Thornton, reconnoitering up the Rio Grande River, is surrounded by 500 Mexican regular cavalry. Second Lieutenant George T. Mason and eight enlisted men are killed, two men wounded, Captain Thornton, two other officers and forty-six men are captured. By this victory the Mexicans are much elated; the flame of war is lighted in the United States. May 11 President Polk announces a state of war, and a bloody invasion of American soil by the Mexican forces that had crossed the Rio Grande. May 13 Congress passes a bill authorizing men and money with which to carry on the war, and declaring that the war has been begun by Mexico. There were objections to the bill on the ground that the President had ordered troops into the disputed territory without having consulted Congress, and that war might have been avoided. But all parties agree that now they must support the Flag. General Taylor calls on the governors of Louisiana and Texas for 5000 volunteers. April 28 Captain Samuel Walker and some seventy Texas Rangers and Volunteers are attacked and beaten by 1500 Mexican soldiers near Point Isabel, the American base of supplies. Captain Walker and six men make their way to General Taylor with report that his line of communication has been cut. May 1, having almost completed the fort opposite Matamoros above the mouth of the Rio Grande, General Taylor leaves a garrison of 1000 men and marches in haste to rescue his supplies at Point Isabel. The Mexican troops are appearing in great numbers, and matters look serious for the little American army. May 3 the Mexican forces at Matamoros open fire upon the fort, thinking that General Taylor has retreated. May 8 General Taylor, hurrying back to the relief of the fort, with his 2300 men defeats 6500 Mexicans under General Arista in the artillery battle of Palo Alto or Tall Timber, fought amidst the thickets and prairie grasses about sixteen miles from Point Isabel. American loss, four killed, forty wounded; Mexican loss, more than 100 in killed alone.