The Battle of the Alamo was considered something of a decisive point in the Texas Revolution, which took place in 1835-1836. For more information on the background of the Texas Revolution and how it rests in the context of the broader Mexican politics of the era, as well as sister revolutions across Mexico, read my answer here Although the Battle of the Alamo most often remembered is not the first battle for the old mission-turned-fort, and it was a disastrous loss for the Texan rebels, but it played a key part in the national consciousness and the morale of the remaining troops that would ultimately help lead to victory and consolidation, and the establishment of the Republic of Texas from 1836-1846.

The first Battle of the Alamo was part of the Siege of Bexar, modern San Antonio. When the siege was won, the Texan forces occupied the old Alamo mission, which Mexico had previously converted into a fort. Antonio Lopez de Santa Anna, part of the dictatorial regime established by the Centralist faction, did not take kindly to any rebels at all, and certainly not to the Texans. As news came of Santa Anna's approach to the old fort, news was seen as grim, the battle doomed, even before he officially laid siege. General Houston could not spare the supplies or men to effectively defend the fort, and yet it was of vital importance - the fort was, in a way, the gateway to all of Texas. If it fell, there was little to no fortification elsewhere to stop Santa Anna's brutal approach across the rest of the territory. James Bowie wrote:

Colonel Neill and myself have come to the solemn resolution that we will rather die in these ditches than give it up to the enemy.

A promise he held to the end.

Santa Anna's approach was just as ruthless to his own men as his intentions were to the enemy. He marched inland toward Bexar, caring not for logistical difficulties. Short supplies, poor training, and indigenous raids took their toll on the Mexican army. However, he made it - on February 23rd of 1836, Santa Anna marched into Bexar, where many residents fled for their lives only hours prior. The unprepared and ill-supplied garrison, outnumbered close to 10:1, was met with a red flag of no quarter. A cannon was fired from the walls by William B. Travis, one of the acting commanders of the fort. Bowie, the other acting commander, sent a messenger to Santa Anna, and Travis, upset by the unilateral action he'd taken, did the same. Both requested honorable surrender, and Santa Anna's representatives responded that only unconditional surrender would be accepted. This was possibly a death sentence all the same, as Santa Anna was known for conducting mass summary executions even on civilians in rebel-held regions.

The two commanders got the report, and together, they fired the cannon again.

This fatal decision, to stand and fight, is what people call to remember. When faced with a challenge, and faced with near certain death, the defenders of the Alamo stood firm. They held out hope that reinforcements might arrive, or that the fort could hold against the assault. The Mexican army began to entrench itself, and set up artillery batteries, while the defenders took the cannonballs shot at them and them right back. When Mexico tried to camp closer to the wall, the Texans sent out a night raid to burn the huts. A cold front blew through, demoralizing the troops. Travis sent letters out across Texas, including this famous line:

I am determined to sustain myself as long as possible & die like a soldier who never forgets what is due to his own honor & that of his country. VICTORY OR DEATH.

This line, a symbol of revolutionary martyrdom and sacrifice, would find wide popularity not just in Texas, not just in North America, but even across the seas in distant lands. However, no help ever came, no reinforcements came to save the Alamo. The situation was ever more dire, but the garrison stood its ground regardless, their sentiments echoed by Travis's words. Quite the contrary, Mexican reinforcements showed up, bringing the enemy heartily over 2000 troops. A string of defeats elsewhere in Texas allowed Mexico to divert more troops to the Alamo, which now had over 3000 sieging it. Eventually, a scant handful of men arrived to reinforce the Alamo itself, the scouts led by David Crockett led them back and behind the lines, into the fort, bringing the number of defenders to a reported 260 men. The following day, March 4th of 1836, a woman left the fort to try to negotiate a surrender one more time. Santa Anna coldly rejected all attempts at parley, seeking blood and glory above all else. The next day, Travis gathered all of the fighters in the garrison, and drew a line in the dirt. He told the garrison that only those willing and ready to die should cross, and all others would be excused from the battle, permitted to leave the Alamo without shame, snuck out the back to safety. Of the fighters, all but one crossed over. This lone survivor, Louis Rose, who (along with the couriers who traveled back and forth between it and the rest of Texas) became among the only sources of information about what happened before the fatal battle.

At 5:30 AM of March 6, 1836, Mexico made its assault under cover of a clouded moon. The sound of gunfire woke the garrison, and most of the civilians trapped inside fled to the chapel for safety. Travis gathered his men, in English and in Spanish, telling them to give hell and never surrender. The Mexican ranks advanced, and the Texan cannons shot whatever metal they could find. Balls, door hinges, nails, and horseshoes all passed through the Mexican lines. One Mexican general reported that half a contingent of cavalry was brought down by a single firing of this makeshift grapeshot. The Texans fired cannon and gun, but the Mexicans made it to the walls, so the Texans leaned over the walls and shot down. Travis, shooting his shotgun down the wall, was struck by a bullet from a Mexican infantryman. Supposedly, he drew his sword and killed a scaling officer before dying of his injury. As the Mexican ladders reached the walls, the defenders held them off enough to force a retreat and regroup. A second attack came, and the weary garrison managed to repel it once more. A third assault followed, and the garrison, struggling to stop the soldiers scaling and to reload their weapons at the same time, failed. Mexican general Juan Amador was the first to climb the wall, whose loose masonry provided many holds and grips. He opened a door, and Mexican soldiers poured in.

The garrison abandoned the north and west portions of the wall, while the cannons toward the south were turned to fire north at the incoming advance already within the fort. This left the south undefended, and the south and east would soon fall, leaving the remaining soldiers to retreat toward the interior, to the barracks and the chapel where holes had been drilled in the walls to shoot through. The group attempting to get to the barracks was cut off, and sallied toward the nearby river instead - where a group reported to be 50 in size made a last stand against the cavalry stationed outside. Another group in the stables fired volleys into the advance, and then sallied out, fighting the cavalry in another last stand. Crockett remained in command of the last group in the courtyard of the fort. As combat drew too close to reload, he and his soldiers used their guns as clubs instead. A volley from the Mexican army sent them retreating into the chapel, while the defender of the Texan flag over the fort killed four soldiers before falling himself. The Mexicans used cannons to blow down the doors of the barracks, and then would shoot in through the gaps and charge in with bayonets.

Bowie, who had fallen critically ill during the siege, was bedridden for the battle. He was left in the barracks throughout, with several pistols and a knife. As the Mexican army charged into his room, he shot them with each pistol once, and then defended himself with his signature bowie knife. Legend holds he may have killed up to 11 enemies before being swarmed, stabbed repeatedly by bayonets, and shot several times.

The only remaining soldiers were in the chapel. As the door was breached, the Texans fired a cannon from the back straight into the lines breaching through. They then fired a volley, and fell to the bayonet charge. One survivor, a Brigido Guerrero, who had defected the previous year, managed to convince the Mexicans that he had been taken and held as a prisoner, rather than a brother-in-arms.

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Hello, I am a Texas Historian and can definitely help you with this question. I’ve studied the Texas Revolution my whole life, and I actually live in an area that had a lot of Texas Revolutionary history attached with it.

The Texas Revolution initially began as just a northern branch of a civil war between Centralists and Federalists. Before crossing the Rio Grande, the war had already spilled blood all across Mexico, and it was a very desperate time for the leaders of the Mexican Federalists who were being hunted down by President Antonio Lopez de Santa Anna.

At the time, Texas was a major supporter of the Federalists and had an entire population of colonists with a zeal for a fight and the weapons and numbers needed to fight with. In 1835, as more and more Federalist strongholds were captured by the Centralists south of the Rio Grande, the key Federalist leaders (Jose Antonio Navarro, Lorenzo de Zavala, and others) fled Mexico and found refuge among the Tejanos and the American emigrants.

The arrival of the Federalist leaders in Texas added to the growing support of Texas joining the war against the Centralists. Other factors, on the American perspective, included Santa Anna’s total rejection of the 1824 Mexican Constitution, his strict enforcement of the 1830 immigration ban, and his complete outlawing of slavery and indentured servitude. These factors are what initially led to the conflict that began in the October of 1835.

As president, Santa Anna was not allowed to leave Mexico City to pursue military affairs. Therefore, in the January of 1835, he surrendered his role as the President of Mexico and became the commanding general of the Mexican Army. Through the winter, spring, and summer of 1835, Santa Anna personally led his soldiers in multiple battles against the Federalist forces in Mexico. It was not until the late summer of that year that he turned his attention to Texas, but he knew that Texas was going to be a harder campaign to win.

To begin his initial probe into Texas, Santa Anna ordered General Martin Perfecto de Cos to take command of the Texas garrisons. When Cos arrived in San Antonio, he quickly dispatched his subordinates and seized full control of the Texas garrisons...a maneuver that would later haunt him in the December of that year.

In early October, 1835, General Cos received a direct order from Santa Anna to begin confiscating all the governmental ordinances that had been leant to civilian settlements for protection against Native Americans. Cos dispatched a small cavalry unit to the larger community of Gonzales, which is east of San Antonio, with orders to retrieve a small 6 pounder cannon that had been leant to the town for protection. Texan Federalists found out about this directive, and met the cavalry unit west of Gonzales with the cannon loaded and ready and a white banner that read “Come and Take It”.

The Battle of Gonzales was fought on October 2, 1835 and is officially considered the starting point of what would become the Texas Revolution. It was a major victory for the Texans, and united factions of both Tejanos and American immigrants began forming the Texas Revolutionary Army.

In the autumn of 1835, a small contingent of Texas rebels (one of the commanders of which was a freed African-American named Samuel McCulloch Jr.) successful moved up from the Texas coastline and captured the Mexican garrison at the Presidio La Bahia in Goliad. Besides San Antonio, La Bahia was the second most important Mexican outpost in Texas at the time. Not long afterwards, another rebellious unit captured the Mexican fortress at Nacogdoches in what is today East Texas.

By December, 1835, the Texas Revolutionary Army had grown immensely, and was now laying siege to General Cos at San Antonio. After a long and grueling siege, the Texans moved into San Antonio and eventually captured General Cos and the Alamo. Afterwards, at a promise to retreat entirely south of the Rio Grande, General Cos surrendered Texas to the Federalists.

All was quiet on the Texas front until the February of 1836. With a massive army of roughly 10,000 fully equipped and largely veteran soldiers, Santa Anna started marching northward and crossed the Rio Grande into Texas at the end of January.

He divided his army only partially, sending about 2-3,000 troops under General Jose Urrea to capture the Texas coastline. Santa Anna then proceeded upon San Antonio with about 7,000 men. He arrived there in late February, and began laying siege to the 200 man garrison at the Alamo.

I won’t go into the 13 day siege of the Alamo very much, because it’s pretty well documented and easily accessible. But, between February 28 and March 6, 1836, the 200 Texans withstood Santa Anna’s attacks courageously and valiantly. The final attack on the Alamo came on the morning of March 6 and all the men in the Alamo were killed.

While Santa Anna was distracted at the Alamo, other events spurred across Texas that were just as significant as the Alamo. On March 2, a mixed assembly of Tejano and American leaders met at Washington-on-the-Brazos and declared Texas’ complete independence from Mexico. Additionally, on that same night, a large force of revolutionary troops were killed in the Battle of Agua Dulce in south Texas by Urrea’s forces.

As Santa Anna was besieging the Alamo, Texas General Sam Houston built and trained an army of roughly 900 men in Gonzales. An additional 3-400 men were gathered and trained at the La Bahia mission in Goliad.

After the Alamo was defeated on March 6, Santa Anna began driving into the eastern settlements of Texas in pursuit of Houston’s army. The Texans, however, were swiftly retreating and burning their settlements and camps in their trace.

On the coastline, Urrea’s forces were swiftly moving towards Goliad. A large battle at Refugio, which took place on March 15, severely hampered Urrea’s advancement. In a battle against 150 Texas troops, Urrea lost 6-700 soldiers before finally defeating the Texans. Additionally, scattered bands of Karankawa Indians whose members had initially supported the Mexicans, turned sides and started launching daring surprise attacks on Urrea’s forces.

As both Santa Anna and Jose Urrea were moving towards the Brazos River, the springtime weather also joined the war in favor of the Texans. Severe thunderstorms swelled the rivers, turned the trails into mud, and the Mexican forces were unable to advance swiftly enough to catch-up to Houston’s army.

The biggest thorn to prick the Mexican campaign to capture Texas occurred on March 27, 1836 in Goliad. Texas commander, James Walker Fannin, had made a desperate stand against Urrea’s forces at Coleto Creek after having abandoned the La Bahia fortress. He had surrender his force of 300 troops to Urrea after the Mexican artillery battalions arrived and they were held as prisoners at La Bahia for almost a week. But on Palm Sunday, 1836, a direct order to execute all of the Texans was received from Santa Anna and what became known as the Goliad Massacre unfolded.

Out of 300 men, only 32 Texans managed to escape. The event sparked flames with-in the Texas Army that turned into a bonfire of much larger importance than even the Alamo had been.

After the Goliad Massacre, Houston knew he was going to have to fight. He chose a site in the southeastern portions of what is now the City of Houston, and waited for Santa Anna.

Learning that Houston had stalled, Santa Anna foolishly decided to advance a small arm of his strength to get-in behind Houston. Additionally, he decided to personally lead the charge as well.

When Sam Houston learned that Santa Anna had separated from his main columns, he burned a bridge and created a final battlefield between he and Santa Anna. In the afternoon of April 21, 1836, Sam Houston launched his attack on Santa Anna and defeated the Mexican troops in 18 minutes...and only lost 2 men. It became known as the Battle of San Jacinto.

Santa Anna was captured a few days after the Battle of San Jacinto, but contrary to popular myth, he was NOT the President of Mexico and could not do anything but order his army to retreat back to the Rio Grande. Although he recognized Texas’ independence, the Mexican government never did. Because of the floods and terrible weather, the Mexican Army followed Santa Anna’s directives and turned back towards Mexico.

Between 1836 and 1845, it can be said that the Texas Revolution was still sporadically fought. An 1841 Mexican excursion actually re-captured San Antonio but only held it very briefly. A counter expedition was launched by the Texas Government but it failed just as miserably.

It wasn’t until Texas’ annexation into the US that the Texas Revolution really ended. But, for all practical matters, the Texas Revolution has been accepted as taking place between 1835 and 1836.

One of the most uniquely powerful things about the Texas Revolution was that the Texas Revolutionary Army was one of the earliest and most culturally mixed armies in American History. Among its ranks were: Tejanos, Southerners, Northerners, Foreigners, freed African-Americans, enslaved African-Americans, women, and even Native Americans! That’s probably one of the most awesome things about the Texas Revolution on the impact of American History.

Anyhow, sorry this was such a long reply, but I hope this helps.

Sources: There are too many, but the best source of information (in my opinion) on the Texas Revolution is Stephen Harding’s “Texian Iliad” which can be purchased from Amazon.