The relationship between ahuras / asuras and daevas / devas in Indo-Aryan times, was discussed at length by F.B.J. Kuiper.[26] This theory and other Avesta-related hypotheses developed over the 20th century, are all now questioned particularly for lack of archaeological evidence.[27][3]: 5–8, 12, 15, 18–19, 37 Asko Parpola has re-opened this debate by presenting archaeological and linguistic evidence, but notes that the links may go earlier to Uralic languages roots.[28]