conquest. Land acquired from these conquests was to be held by the three cities together. A tribute was divided so that two kings of the alliance would go to Tenochtitlan and Texcoco and one would go to Tlacopan. The three kings assumed the title "huetlatoani" ("Elder Speaker", often translated as "Emperor") in turn. Each temporarily held a position above the rulers of other city-states ("tlatoani") in this role. In the following 100 years, the Triple Alliance of Tenochtitlan, Texcoco, and Tlacopan dominated the Valley of Mexico and extended its power to the shores of the Gulf of Mexico and the Pacific. Tenochtitlan gradually became the dominant power in the alliance. Two of the primary architects of this alliance were the half-brothers and nephews of Itzcoatl Tlacaelel and Moctezuma. Moctezuma eventually succeeded Itzcoatl as the Mexica in 1440. Tlacaelel occupied the newly created "Cihuacoatl" title, equivalent to something between "Prime Minister" and "Viceroy". Imperial reforms Shortly after the formation of the Triple Alliance, Itzcoatl and Tlacopan instigated sweeping reforms on the Aztec state and religion. It has been alleged that Tlacaelel ordered the burning of some or most of the extant Aztec books, claiming that they contained lies and that it was "not wise that all the people should know the paintings". If he ordered book-burnings, it would have been primarily limited to documents containing political propaganda from previous regimes. He rewrote the history of the Aztecs thereafter, naturally placing the Mexica in a more central role. After Moctezuma I succeeded Itzcoatl as the Mexica emperor, more reforms were instigated to maintain control over conquered cities. Uncooperative kings were replaced with puppet rulers loyal to the Mexica. A new imperial tribute system established Mexica tribute collectors that taxed the population directly, bypassing the authority of local dynasties. Nezahualcoyotl also instituted a policy in the Acolhua lands of granting subject kings tributary holdings in lands far from their capitals. This was done to create an incentive for cooperation with the empire; if a city's king rebelled, he lost the tribute he received from foreign land. Some rebellious kings were replaced by or appointed governors rather than dynastic rulers. Moctezuma issued new laws that separated nobles from commoners and instituted the death penalty for adultery and other offenses. A religiously supervised school was built in every neighborhood by royal decree. Commoner neighborhoods had a school called a "" where they received basic religious