Andrew Sherratt's model of a secondary products revolution involved a widespread and broadly contemporaneous set of innovations in Old World farming.
[1] The SPR model incorporates two key elements: Many of these innovations first appeared in the Near East during the fourth millennium BCE and spread to Europe and the rest of Asia soon afterwards.
The dangers of dating the innovations on the basis of evidence such as iconography and waterlogged organic remains with restricted chronological and geographical availability have been pointed out.
Initially the concepts of the SPR were tested by analysing the appearance of certain artefact types (e.g. ploughs, wheeled vehicles).
A study of more than 2,200 pottery vessels from sites in the Near East and Southeastern Europe indicated that milking had its origins in northwestern Anatolia.