Tlatoani, paramount ruler of the central Mesoamerican Nahua Altepetl (regional state or province). Tlatoque (plural) rulership was dynastic, but succession practices varied; the tlatoani of Tenochtitlán was "elected" by a small body of elites, with brothers and nephews likely to succeed. The tlatoani had broad civil, military, and religious powers, and the tlatocayotl (rulership) brought many privileges, including the ability to keep multiple wives and rights to tribute and labor, to private property, and to the best material items available. After the Spanish conquest, tlatoque typically became the first governors of the reorganized indigenous communities. Their dominance faded as other elites successfully competed for access to this office.
There is an extensive literature dealing with the tlatoani. One of the best primary sources is Bernardino De Sahagún, Florentine Codex. Book 8, Kings and Lords, translated and edited by Arthur J. O. Anderson and Charles E. Dibble (1954). An excellent study is Susan D. Gillespie, The Aztec Kings: The Construction of Rulership in Mexican History (1989). The evolution of tlatocayotl in the colonial period is examined in Charles Gibson, The Aztecs Under Spanish Rule (1964); Robert Haskett, Indigenous Rulers: An Ethnohistory of Town Government in Colonial Cuernavaca (1991); Susan Schroeder, Chimalpahin and the Kingdons of Chalco (1991); and James Lockhart, The Nahuas after the Conquest: A Social and Cultural History of the Indians of Central Mexico, Sixteenth through Eighteenth Centuries (1992).