The first serious study of chambered long barrows took place in the sixteenth and seventeenth centuries, when the mounds that covered chambers were removed by agriculture.[50] By the nineteenth century, antiquarians and archaeologists had come to recognise this style of monument as a form of tomb.[50] In the latter nineteenth and early twentieth centuries, archaeologists like V. Gordon Childe held to the cultural diffusionist view that such Western European monuments had been based on tombs originally produced in parts of the eastern Mediterranean region, suggesting that their ultimate origin was either in Egypt or in Crete.[51] In this view, the tradition was seen as having spread westward as part of some form of "megalithic religion".[29]