In August 1094, a huge Almoravid army crossed the Gibraltar Strait. Among the transport ships were galleys towing palm-trunk rafts carrying elephants. Yusuf Bin Tashufin appointed his nephew, whose name appears to have been Abu Abdullah bin Muhammad, to lead the campaign. The army was divided into two roughly equal corps. The first, under Muhammad's command, was to take Valencia and rid bin Tashufin of the pesky Cid. This force enjoyed several advantages over the city's defenders. It likely boasted 25,000 or more men, while El Cid's striking force numbered fewer than 4,000 mounted men-at-arms. Also, Almoravid warriors were religious fanatics who, assured of eternal reward in the hereafter, fought to the death. Christian noblemen, meanwhile, typically surrendered when faced with hopeless circumstances, expecting to be ransomed.
Since his armies first faced this charge at Sagrajas, bin Tashufin had modified his organization and tactics to defeat it. Some 80 percent of the Almoravid army was mounted, but because chain-mail armor was expensive and not widely available, most of the soldiers were light cavalry fighting like infantry with little or no bodily protection other than small round shields. Given this handicap, the Muslim warriors could not mount a heavy charge. Bin Tashufin had discovered that his desert cavalry could keep the enemy from organizing and launching its devastating massed charges. Rather than going head-to-head with armored knights, his men fought in skirmishing attacks in which their more agile Berber horses easily out-turned the knights' destriers—large horses bred to carry the weight of heavily armed and armored riders. The mounted skirmishers would lure impulsive knights into protective spear lines of Berber infantry, who then showered the enemy with arrows and armor-piercing javelins. Horse archers would also dart in close to bring down knights' horses, spoiling a charge as it formed. Once these tactics had softened the enemy, the Almoravids' limited armored cavalry might spearhead a charge of their massed light cavalry.
Facing these long odds, Rodrigo began to put together his defense. Literate in Latin and Arabic, Rodrigo had studied the classical sources on battle tactics and siege techniques, sometimes sight-translating passages aloud to his knights. In fact, he had long ago earned the honorific campeador, which came from the Latin campi doctoris (a battle planner and teacher), used in Vegetius's popular fourth-century Roman treatise, De re militari.Given the Almoravids' numerical superiority, convention suggested that Rodrigo fight defensively. But he believed he had to destroy bin Tashufin's army to remove the Almoravid threat to Valencia. That meant taking the enemy by surprise outside the city walls.
Rodrigo had the uncanny ability to spot and exploit his opponent's vulnerabilities—whether in weapons, tactics, or even cultural practices. Instinctively he found a weakness in what was supposed to be the Almoravid army's strength—its strict tactical organization, firm individual discipline, and tight control. He concluded that if he could attack before they had organized and deployed, his knights' advantages—skill at arms, quality and weight of weapons, armor, and mounts, and individual élan—might carry the day.
To attack before the Almoravids could deploy, Rodrigo would have to draw them to a field of battle away from their siege cordon at Valencia. Four miles up the Río Turia from Valencia and northwest of the city lay the plain of El Cuarte (Quart de Poblet today). The Turia fed a network of canals and ditches irrigating huertas (market gardens), beyond which stretched meadows and groves of algarrobos (carob trees). Rodrigo presumed the Almoravids would make their base camp at El Cuarte because the valley was the only place with sufficient forage for their horses, mules, camels, and elephants. To make sure, he had anti-Almoravid Muslims meet the enemy quartermasters, pretend to welcome them as liberators, and direct them there.
Unknown to the Almoravids, the early autumn regularly saw heavy rains in the area around Valencia. And when the rains arrived as late as October, they typically began with a deluge, triggering floods that wiped out harvests. When spies advised that the Almoravids would reach Valencia in the middle of the Muslim holy month of Ramadan, Rodrigo saw another way to tip the balance in his favor. During Ramadan, Muslims abstained from eating and drinking between sunrise and sunset. After fasting all day, observants usually slept late after a long night of heavy eating—a routine that often left them lethargic and irritable. Rodrigo realized that the Almoravids would be at their most vulnerable at the end of Ramadan, October 14.
According to Olaizola, Muhammad, bin Tashufin's nephew, presented himself at Valencia's main gate on October 4. With him were his principal captains and his most imposing units, including a mehala (camel corps). The city, Muhammad said, should surrender without delay. El Cid, however, stood firm. On each of the next eight days, the Almoravid general came to the gate to renew his surrender demand, taunt Rodrigo for delaying, and admonish Valencia's Muslims for collaborating with the infidel during Ramadan. On the 10th day of the siege, Valencia's market gardeners called Rodrigo's attention to birds appearing from unusual directions and flying so low that they grazed the ground—a sign that the overdue rains were about to begin. That night, the sky filled with black clouds loaded with moisture. At dawn on October 14, raindrops pattered on Valencia's empty, eerily silent cobblestone streets. The populace had been warned to stay home. Just inside the city's main gate, 130 handpicked knights led by Álvar Háñez waited, dismounted. Roused at 3 a.m. for a special Mass, the rest now sat on their high-saddled destriers, standing by in courtyards and marketplaces at the city's northwestern gates. A low murmur arose as Friar (and future bishop) Jerónimo moved among the ranks with a tall wooden cross for the men to kiss. "I absolve from sin all those who die with their faces to the enemy," he quietly told them. "God will receive their souls."
As the sun rose out of the Mediterranean, the west-facing gate opened a crack and Álvar's knights slipped out. All carried new shields made by Basque craftsmen from tough haya (beech) wood, with forged iron reinforcements. Standing shoulder to shoulder in a single rank, they made a formidable shield wall. Struggling awake from their Ramadan slumber, the Almoravid sentries squinted into the rising sun. Now Álvar's knights reached the closest belfry. Though the siege machines had frightened the citizens of Valencia, Rodrigo had seen an opportunity in them. Some of Álvar's men pushed bundles of dry straw under the rawhide coverings and set them alight. Flames shot up the wooden scaffolds and ladders. Berber warriors reacted with howls and invocations to the Prophet, but their archers' desultory shots couldn't pierce the Basque shields.
Meanwhile, behind the walls of Valencia, Rodrigo had divided his main force into two. He took charge of the lead element, according to Abu bin Alqama, the only chronicler to witness the scene. Springing onto the back of his famed warhorse, Babieca, he put spur to flank and led his knights through the gates at the trot. Outside, he drew his bejeweled sword, Colada, and gave the battle cry that would animate the Reconquista for the next 400 years, as well as New World conquests after that: "For God and Santiago [St. James], and at them!"
The knights charged through the pandemonium that was now the Almoravid cordon. The ground trembled under the hooves of the destriers as they trampled lanced Berber warriors, tents, field kitchens, and supplies. When the knights had passed through the cordon, they rallied around Rodrigo's banner. Then, with the bewildered Berbers facing this group, the second wing smashed into them from the rear. By the time these knights had joined Rodrigo's wing, the plain was a scene of chaos, littered with corpses, debris, and soldiers trying to surrender.
The rain now turned into a downpour, and Rodrigo wheeled and led his knights at the gallop toward the enemy's main camp at El Cuarte. Leaderless and without orders, Berber cavalrymen seized mounts and set off in wild pursuit. As they arrived at El Cuarte, they were shaken by the spectacle: The Turia, swollen by water surging down from the mountains, had become a torrent rushing to the sea, carrying away pavilions, campaign tents, supply wagons, and stores. For Rodrigo had ordered the irrigation weirs opened or broken. As the Almoravid horsemen streamed onto the plain, Rodrigo's force stormed out from the groves of algarrobos in a classic knights' charge.
Even as the Almoravids struggled to meet this new assault, their situation took another turn for the worse. Álvar and his knights, who had remained outside the walls of Valencia to round up surrendering Muslim warriors, now rode up and fell on them with such force that organized resistance died away. According to Arab chronicler bin Alqama, the Muslims ran in all directions, with Muhammad the first to take flight. Panicked Berbers drowned; elephants flailed about as they sank into newly formed swamps, killing or injuring others. Some Almoravids fought bravely, trying to protect their women and children, but the knights cut down all who resisted.
The abundant booty—gold, silver, gemstones, and more—made Rodrigo and his knights rich. Royal courts all over Europe celebrated the victory; the Almoravids' military might and revitalization of Iberian Islam had been a dire threat to the Christian Reconquista. Alfonso would fail to capitalize on the victory that Rodrigo handed him, however, and Christians would spend another four centuries trying to force out the Muslims. But by destroying the Almoravid army at El Cuarte, Rodrigo established the high-water mark for the Muslim advance in the Iberian Peninsula. In the years after the battle, he captured the last two Moorish castles in the region and defeated another Almoravid invasion. All the while, he evenhandedly ruled a region of Muslims and Christians.