Task: Question Answering
Input (English): Passage: In 1525 Pedro de Alvarado sent a small company to conquer Mixco Viejo (Chinautla Viejo), the capital of the Poqomam. At the Spanish approach, the inhabitants remained enclosed in the fortified city. The Spanish attempted an approach from the west through a narrow pass but were forced back with heavy losses. Alvarado himself launched the second assault with 200 Tlaxcalan allies but was also beaten back. The Poqomam then received reinforcements, possibly from Chinautla, and the two armies clashed on open ground outside of the city. The battle was chaotic and lasted for most of the day but was finally decided by the Spanish cavalry, forcing the Poqomam reinforcements to withdraw. The leaders of the reinforcements surrendered to the Spanish three days after their retreat and revealed that the city had a secret entrance in the form of a cave leading up from a nearby river, allowing the inhabitants to come and go.Armed with the knowledge gained from their prisoners, Alvarado sent 40 men to cover the exit from the cave and launched another assault along the ravine from the west, in single file owing to its narrowness, with crossbowmen alternating with soldiers bearing muskets, each with a companion sheltering him from arrows and stones with a shield. This tactic allowed the Spanish to break through the pass and storm the entrance of the city. The Poqomam warriors fell back in disorder in a chaotic retreat through the city, and were hunted down by the victorious conquistadors and their allies. Those who managed to retreat down the neighbouring valley were ambushed by Spanish cavalry who had been posted to block the exit from the cave, the survivors were captured and brought back to the city. The siege had lasted more than a month and because of the defensive strength of the city, Alvarado ordered it to be burned and moved the inhabitants to the new colonial village of Mixco. 
Question: What was the first name of the person whose men forced the Poqomam reinforcements to withdraw?
Output (English): Pedro.