Because of the controversy over Westropp's Mesolithic and Mortillet's Gap beginning in 1872 archaeological attention focused mainly on the revolution at the Palaeolithic—Neolithic boundary as an explanation of the gap. For a few decades the Neolithic Period, as it was called, was described as a kind of revolution. In the 1890s, a standard term, the Neolithic Revolution, began to appear in encyclopedias such as Pears. In 1925 the Cambridge Ancient History reported:There are quite a large number of archaeologists who justifiably consider the period of the Late Stone Age to be a Neolithic revolution and an economic revolution at the same time. For that is the period when primitive agriculture developed and cattle breeding began.