Cortés arrived at Tlaxcala, a small independent state within the empire's sphere of influence. The Tlaxcaltecas attacked his troops, but Spanish crossbows, broadswords, battle axes, horses, war dogs and firearms quickly won the battle. Cortés said that if the men of Tlaxcala would accept Christianity, become his allies and vassals to his lord, he would forgive their disrespect and overthrow their nemesis, Emperor Moctezuma. Cortés's "lord" was Holy Roman Emperor Charles V, to whom he made his case by letters, over the head of Velázquez, who, in turn, was trying to make a case over the head of Diego Colón, son of Christopher Columbus and thus Admiral of the Ocean Sea. Otherwise, Cortés threatened, he would kill everyone in their entire nation.