showed that northern India already had an advanced culture when the Indo-Aryans migrated into the area. The theory changed from a migration of advanced Aryans towards a primitive aboriginal population, to a migration of nomadic people into an advanced urban civilization, comparable to the Germanic migrations during the Fall of the Western Roman Empire, or the Kassite invasion of Babylonia. This possibility was for a short time seen as a hostile invasion into northern India. The decline of the Indus Valley civilisation at precisely the period in history in which the Indo-Aryan migrations probably took place, seemed to provide independent support of such an invasion. This argument was proposed by the mid-20th century archaeologist Mortimer Wheeler, who interpreted the presence of many unburied corpses found in the top levels of Mohenjo-daro as the victims of conquest wars, and who famously stated that the god "Indra stands accused" of the destruction of the Civilisation. This position was discarded after finding no evidence of wars. The skeletons were found to be hasty interments, not massacred victims. Wheeler himself also nuanced this interpretation in later publications, stating "This is a possibility, but it can't be proven, and it may not be correct." Wheeler further notes that the unburied corpses may indicate an event in the final phase of human occupation of Mohenjo-Daro, and that thereafter the place was uninhabited, but that the decay of Mohenjo-Daro has to be ascribed to structural causes such as salinisation. Nevertheless, although 'invasion' was discredited, critics of the Indo-Aryan Migration theory continue to present the theory as an "Aryan Invasion Theory", presenting it as a racist and colonialist discourse: Aryan migration In the later 20th century, ideas were refined along with data accrual, and migration and acculturation were seen as the methods whereby Indo-Aryans and their language and culture spread into northwest India around 1500 BCE. The term "invasion" is only being used nowadays by opponents of the Indo-Aryan Migration theory. Michael Witzel: The changed approach was in line with newly developed thinking about language transfer in general, such as the migration of the Greeks into Greece (between 2100 and 1600 BCE) and their adoption of a syllabic script, Linear B, from the pre-existing Linear A, with the purpose of writing Mycenaean Greek, or the Indo-Europeanization of Western Europe (in stages between 2200 and 1300 BCE). Future directions Mallory notes that with the development and the growing sophistication