The existence of the Yalain was first proposed by Grant D. Jones. Jones suggested that their territory was based around the town of the same name on the shores of Lake Macanché and extended eastwards into the drainage of the Yaxhá and Sacnab lakes. This area was formerly Kowoj territory and was aggressively occupied by the Itza in the 1630s. Don and Prudence Rice have disputed the location of the Yalain capital being so far east on the basis that it would be too far for the inhabitants of Nojpetén to tend their fields. They suggest an alternative location on the small southern arm of Lake Petén Itza itself. Jones later questioned the independent existence of the Yalain and considered them to be either allies or vassals of the Itza, and best described as a part of the Itza polity. The Yalain polity was under Itza control when the Spanish invaded Petén in 1697, at which time it was ruled by Aj Chan, the son of the sister of the king of the Itza. Don and Prudence Rice have argued that there is sufficient evidence that the Yalain should not be considered identical to the Itza and that the prospective Yalain polity remains plausible.