“We live on islands surrounded by seas of data,” Michael Friendly and Howard Wainer claim in the introduction to their history of data visualization. It is this data flood that has made diagrams for data visualization necessary. However, such a situation is rather new. Innovations in data visualization only took off in the late 1700s, following in the footsteps of new measurement technologies that began to appear in the 1600s. The previous period was characterized by diagrams for logical and textual analysis, with the High Middle Ages as a period of intense innovation in new forms of abstract diagrams. However, the 1500s to the 1700s saw very little innovation in abstract diagrams. Scientific texts were either accompanied by figurative illustrations, such as images of observed naturalia or of scientific equipment, or by tables of measurement results. The abstract diagrams that existed were mainly bracketed tree structures that systematized knowledge.