|Planetary movements shown as cyclic inclinations over time, by an unknown astronomer, appearing in a|
10th-century appendix to commentaries by Macrobius on Cicero’s Somnium Sciponis. This is the earliest
known 2-dimensional charts (plotting time vs. celestial latitude; an apparent anomaly is that it appears to
show the celestial latitude of the Sun varying with time); the scribe used horizontal and vertical lines as
aids, resulting in a picture strikingly similar to modern graph paper as it did not become commonly used
before the mid 19th century, some 700 years later. This picture is a notable anomaly, as the earliest
comparable "graph" diagram do not emerge prior to the late medieval period, some 250 years after
this drawing was made. Source: Wikimedia.
Among the earliest graphical depictions of quantitative information is the above anonymous 10th-century multiple time-series graph of the changing position of the seven most prominent heavenly bodies over space and time. The vertical axis represents the inclination of the planetary orbits; the horizontal axis shows time, divided into 30 intervals. The sinusoidal variation with different periods is notable, as is the use of a grid,suggesting both an implicit notion of a coordinate system and something akin to graph paper, ideas that would not be fully developed until the 1600-1700s. In the 14th century, the idea of plotting a theoretical function (as a proto bar graph) and the logical relation between tabulating values and plotting them appeared in a work by Nicole Oresme (1323-1382), Bishop of Liseus, followed somewhat later by the idea of a theoretical graph of distance vs. speed by Nicolas of Cusa.