The Spanish invaders who managed to escape from Tenochtitlan were weak, dispirited and wounded. The new Emperor of the Mexica, Cuitláhuac, decided that he had to try and crush them once and for all. He sent a large army of every warrior he could find under the command of the new cihuacoatl (a sort of captain-general), his brother Matlatzincatzin. On or about July 7, 1520, the two armies met in the flatlands of the Valley of Otumba. Spotting the brightly dressed Matlatzincatzin and his generals at the other end of the battlefield, Cortes decided on a risky move. Summoning his best remaining horsemen (Cristobal de Olid, Pablo de Sandoval, Pedro de Alvarado, Alonso de Avila and Juan De Salamanca), Cortes rode at the enemy captains. The sudden, furious assault took Matlatzincatzin and the others by surprise. The Mexica captain lost his footing and Salamanca killed him with his lance, capturing the enemy standard in the process. Demoralized and without the standard (which was used to direct troop movements), the Aztec army scattered. Cortes and the Spanish had pulled out a most unlikely victory.