The word encyclopedia comes from two Greek words meaning “a circle of learning.” The oldest known encyclopedia was written in Greece about 2000 years ago. It’s no longer in existence. The oldest encyclopedia in existence was written in the 1st century by Roman scholar Gaius Plinius Secundus (Pliny the Elder). His encyclopaedia, called Natural History, has 37 volumes.
The largest ever encyclopedia is the Yung-Lo Ta-Tien encyclopedia. It was commissioned in 1403 by Emperor Yongle and is also known as the Yongle Encyclopedia. Written by 2000 writers, it was completed in 1408 and bound in 11,095 volumes, of which some 400 volumes survived.