 The argument was first put forward by German philologist Otto Schrader in 1883.The argument was subject to continued scholarly debate throughout the late 19th and early 20th centuries, particularly in German academia.In 1953, German indologist Paul Thieme submitted that the descendants of "laḱs-" found in the Caucasus described the trout ("Salmo trutta") rather than the Atlantic salmon ("Salmo salar").