A new page was now to be turned in the eventful life of the young officer; when he was to have, as Emerson beautifully says of love, "the visitation of that power to his heart and brain which created all things anew; which was the dawn in him of music, poetry, and art; which made the face of nature radiant with purple light; the morning and the night varied enchantments; when a single tone of one voice could make the heart bound, and the most trivial circumstance associated with one form is put in the amber of memory; when he became all eye when one was present, and all memory when one was gone; ... when the moonlight was a pleasing fever, and the stars were letters, and the flowers ciphers, and the air was coined into song; when all business seemed an impertinence, and all the men and women running to and fro in the streets were pictures."

At West Point, Grant's class-mate was F. T. Dent, whose family resided five miles west of Jefferson Barracks. "Two of his unmarried brothers," says Grant, "were living at home at that time, and, as I had taken with me from Ohio my horse, saddle, and bridle, I soon found my way out to White Haven, the name of the Dent estate. As I found the family congenial, my visits became frequent. There were at home, besides the young men, two daughters, one a school miss of fifteen, the other a girl of eight or nine. There was still an older daughter, of seventeen, who had been spending several years at boarding-school in St. Louis, but who, though through school, had not yet returned home.... In February she returned to her country home. After that I do not know but my visits became more frequent; they certainly did become more enjoyable. We would often take walks, or go on horseback together to visit the neighbors, until I became quite well acquainted in that vicinity.... If the fourth infantry had remained at Jefferson Barracks it is possible, even probable, that this life might have continued for some years without my finding out that there was anything serious the matter with me; but in the following May a circumstance occurred which developed my sentiment so palpably that there was no mistaking it."

This "circumstance" was the annexation of Texas, the probability of a war with Mexico, and the necessity of leaving Jefferson Barracks for the Texan frontier. Alas! now that days full of hope, and the sweet realization of a divine companionship had come, they must have sudden ending. Grant took a brief furlough, went to say good-bye to his father and mother, and then to White Haven to see Julia Dent. In crossing a swollen stream, his uniform was wet through, but he donned the suit of a future brother-in-law, and appeared before his beloved to ask her hand in marriage, to receive her acceptance, and then to hasten to the scene of action. He saw her but once in the next four years and three months; four anxious years to her, when death often stared her lover in the face.

As soon as Texas was admitted to the Union, in 1845, the "army of occupation," as the three thousand men under General Zachary Taylor were called, advanced to the Rio Grande and built a fort. When the first hostile gun was fired, Grant says, "I felt sorry that I had enlisted. A great many men, when they smell battle afar off, chafe to get into the fray. When they say so themselves, they generally fail to convince their hearers that they are as anxious as they would like to make believe, and as they approach danger they become more subdued. This rule is not universal, for I have known a few men who were always aching for a fight when there was no enemy near, who were as good as their word when the battle did come on. But the number of such men is small."

The first battle was at Palo Alto, meaning "tall trees or woods," six miles from the Rio Grande. Early in the forenoon of May 8, Taylor's three thousand men were drawn up in line of battle, opposed by superior numbers. The infantry was armed with flintlock muskets and paper cartridges charged with powder, buckshot, and ball. "At the distance of a few hundred yards," says Grant, "a man might fire at you all day without your finding it out." The artillery consisted of two batteries and two eighteen-pounder iron guns, with three or four twelve-pounder howitzers throwing shell. The firing was brisk on both sides. One cannon-ball passed near Grant, killing several of his companions. After a hard day's fight, the enemy retreated in the night. The war had now begun in earnest, and the man who at the first hostile gun "felt sorry that he had enlisted" was ready to brave danger on any field.

In the hard-fought battle of Monterey, between sixty-five hundred men under Taylor and ten thousand Mexicans, Grant's curiosity got the better of his judgment, and, leaving the camp, where he had been ordered to remain, he mounted a horse and rode to the front. He made the charge with the men, when about a third of their number were killed. He loaned his horse to the adjutant of the regiment, Lieutenant Hoskins, who was soon killed, and Grant was designated to act in his place.

The ammunition became low, and to return for it was so dangerous that the general commanding did not like to order any one to fetch it, so called for a volunteer. Grant modestly says, "I volunteered to go back to the point we had started from.... My ride back was an exposed one. Before starting, I adjusted myself on the side of my horse furthest from the enemy, and with only one foot holding to the cantle of the saddle, and an arm over the neck of the horse exposed, I started at full run. It was only at street-crossings that my horse was under fire, but these I crossed at such a flying rate that generally I was past and under cover of the next block of houses before the enemy fired. I got out safely, without a scratch."

When Monterey was conquered, and the garrison marched out as prisoners, young Grant was moved to pity, as he says in his Memoirs, thus showing a gentle nature, which he bore years later when thousands were falling around him, and he was still obliged to say, "Forward."

After the capture of Vera Cruz and the surprise at Cerro Gordo, where three thousand Mexicans were made prisoners, the army advanced toward the City of Mexico. Between three and four miles from the city stood Molino del Rey, the "mill of the King," an old stone structure, one story high, flat-roofed, and several hundred feet long. Sandbags were laid along the roof, and good marksmen fought behind them. Near by was Chepultepec, three hundred feet high, fortified on the top and on its rocky sides. From the front, guns swept the approach to Molino. Yet, on the morning of September 8, the assault upon Molino was made, young Grant being among the foremost. The loss was severe, especially among commissioned officers.

Grant says, "I was with the earliest of the troops to enter the mills. In passing through to the north side, looking toward Chepultepec, I happened to notice that there were armed Mexicans still on top of the building, only a few feet from many of our men. Not seeing any stairway or ladder reaching to the top of the building, I took a few soldiers, and had a cart that happened to be standing near brought up, and, placing the shafts against the wall, and chocking the wheels so that the cart could not back, used the shafts as a sort of ladder, extending to within three or four feet of the top. By this I climbed to the roof of the building, followed by a few men, but found a private soldier had preceded me by some other way. There were still quite a number of Mexicans on the roof, among them a major and five or six officers of lower grades, who had not succeeded in getting away before our troops occupied the building. They still had their arms, while the soldier before mentioned was walking as sentry, guarding the prisoners he had surrounded, all by himself. I halted the sentinel, received the swords from the commissioned officers, and proceeded, with the assistance of the soldiers now with me, to disable the muskets by striking them against the edge of the wall, and throwing them to the ground below."