Comparison has been important to the governance of education on a national and then international scale since the formation of the World Exhibitions in the mid 19thC. This paper will look at four interludes in the rise of comparison and comparability since the mid 19thC. These periods are roughly chronological and can be distinguished but they are also overlap even within one case, and certainly across cases. The four interludes are – World Exhibitions – In which nations present and compare progress. This is a constant features of a range of world exhibitions from 1851 to 1939 [and maybe beyond] Travellers - on behalf of the nation state, providing observational evidence and trying to deliver judgments on progress or useful difference for the sake of national improvement. Scientific Standardization – the establishment of comparative measuring instruments and agreed standards is common to many areas of trade and science but the creation of the IQ test begins to create a common space for comparison [beyond object and observation]. Data Flows – education in Europe [and beyond] appears to be in a state of constant comparison between states; as a tool of Europeanization, with a complex space of flows of agents and data, and producing an enabling space of policy engagement.; and in the production of a new visualization of systems through data