Original sentence: The oldest Maya codices known have been found by archaeologists as mortuary offerings with burials in excavations in Uaxactun, Guaytán in  San Agustín Acasaguastlán, and Nebaj in Quiché, Guatemala, at Altun Ha in Belize and at Copán in Honduras
Edited sentence: The oldest Maya codices known have been found by archaeologists as mortuary offerings with burials in excavations in Uaxactun, Guaytán in  San Agustín Acasaguastlán, and Nebaj in El Quiché, Guatemala, at Altun Ha in Belize and at Copán in Honduras