 Watson's work was met with some early scepticism, such as from the historian Jeremy Johns in 1984.Johns argued that Watson's selection of 18 plants was "peculiar", since the banana, coconut, mango and shaddock were unimportant in the Islamic region at the time, detracting from the discussion of the staple crops.Johns further noted that the evidence of diffusion of crops was imperfect, that Watson made "too many minor slips and larger errors" such as getting dates wrong or claiming that a 1439 document was Norman, and had failed to make best use of the evidence that was available, such as of the decline of classical agriculture, or even to mention the changing geomorphology.