The Middle Bronze Age Migrations are postulated waves of migration during the Middle Bronze Age. This proposal was advanced in the mid-20th century by scholars such as Mellaart, who argued for a connection between the spread of the Indo-European languages and archaeologically attested destructions and cultural changes around the 20th century BC. However, more recent research has disfavored the notion of Indo-European invasions, interpreting the evidence as favoring a more gradual process of assimilation.