Tlaxcalans were rewarded though, even as second class citizens under the spanish empire, they established several communities and were one of the main forces to assist the Spaniards in the conquest of Michoacan and the warfare against the Chichimecs. There are a number of recorded nahua towns and settlements all the way up north in Sinaloa and Zacatecas, and down south to Guatemala, Product of the nahua groups like the Tlaxcaltecs that had participated in these campaigns. Thats why you get all these cities and locations with names in Nahuatl all around the Mexican republic, even in places with no Nahua (indiginous) majority.
They were edited out from the Conquistador chronicles, but they were not forgotten for their assistence in the conquest. Check out the history of Tlaxcala Codex by Diego Mu˝oz Camargo for a Tlaxcalan point of view of the conquest