Set theory originated from a need to put mathematics on a firm, rational foundation. To illustrate the concepts of set theory, various types of logical diagrams emerged, the most prominent being the well-known Venn diagram.

John Venn invented the famous diagram that depicts the relationships between sets. Later, it was named in his honour.

John Venn was a mathematician remembered best for his contributions to the study of mathematical logic and probability. Venn was born in England in 1834 and studied at Cambridge University until 1857. He was ordained as a priest in 1859, and he served as a curate for a year before returning to Cambridge to lecture on Moral Science.

While at Cambridge, Venn spent his time both teaching and studying probability theory and logic. There, he developed a method of using diagrams to illustrate set theory, called Venn diagrams.