<P> The Spanish campaign began in February 1519 , following the Spanish arrival in Yucatán in 1517 . Two years later the Spanish set sail , thus beginning the campaign of colonization of the Americas . The Spanish campaign declared victorious on August 13 , 1521 , when a coalition army of Spanish forces and native Tlaxcalan warriors led by Hernán Cortés and Xicotencatl the Younger captured the emperor Cuauhtemoc and Tenochtitlan , the capital of the Aztec Empire . </P>
who was the aztec ruler when the spanish arrived
emperor Cuauhtemoc