Isidore of Seville

Saint Isidore of Seville was the greatest encyclopedist of the Middle Ages, and a polymath.

What is an encyclopedist? It is just what it sounds like – a person who writes an encyclopedia. The Oxford English Dictionary adds an additional definition: "One who attempts to deal with every branch of knowledge, or whose studies have a very extensive range."

That was Isidore in a nutshell.

He wrote his own encyclopedia, The Etymologies, and without anyone’s help. Today, of course, one couldn’t do that; there is just too much to know. But, 1500 years ago, there wasn’t so much to know, so one person could master the majority of his culture’s knowledge. Isidore was a priest and historian and earns a place in the book of polymaths because of a very simple rule (we can call it Isidore’s rule) – anyone who writes an encyclopedia by himself is a polymath.