This hypothesis is not shared by some Egyptologists such as Manfred Bietak, Daphna Ben Tor and James and Susan Allen, who argue that the 14th Dynasty cannot have emerged before the mid 13th Dynasty, c. 1720 BC, after the reign of Sobekhotep IV. In particular, they argue that the evidence from the strata levels in which 14th Dynasty seals were discovered conclusively establishes that the 14th Dynasty was only contemporary with the 13th Dynasty in the last half century of the latter's existence, i.e. after c. 1700 BC. Additionally, Manfred Bietak has dated the inscriptions and monuments of Nehesy, possibly the second ruler of the dynasty, to around 1700 BC as well.