Varro, Marcus Terentius (116–27 B.C.), a Roman scholar. He was called “the most learned of the Romans” because of his encyclopedic knowledge. In De re rustica, a book on agriculture, he speculated that contagion from stagnant water might affect a person's health. (This theory of disease was first formulated scientifically in 1546 by Girolamo Fracastoro.) Varro's Disciplinae was a nine-volume work on the arts and sciences. Short biographies of 700 famous Greeks and Romans were included in Imagines. Varro wrote about 490 books, but only a few survive in fairly complete form.

Varro was born in Reate, and studied in Rome and Athens. In the civil war of 49–48 B.C. he fought in Pompey's army, which was defeated by Julius Caesar. Caesar pardoned him, and commissioned him to collect books for the great public library he planned. After Caesar's death Varro was outlawed by Marc Antony and fled the country. He later was able to return and resume his writing.