The Ancient Library of Alexandria

Relatively little is known about the ancient library itself, beyond its reputation for scholarship. It was founded by Ptolemy I in the 4th century BC and is said to have held a collection of 500,000 volumes—at a time when books were rare, costly commodities and all written by hand. Succeeding pharaohs gathered existing knowledge from around the Greek world but also invited scientists and scholars to contribute current research, ensuring that Alexandria was at the cutting edge of learning.

Theories about its destruction abound, but most assume it stood for roughly 500 years before being consumed by fire. What is known is that the Great Library—and the complex of lecture halls, laboratories, and observatories called the Mouseion, of which it was part—was a source of literary and scientific wisdom that changed the world. It was here, for example, that Euclid set forth the elements of geometry still taught in schools today, and Eratosthenes measured the circumference of the Earth. And it was here that the conqueror Julius Caesar had a new, more accurate calendar drawn up—the Julian calendar—that became the framework for the measurement of time throughout the Western world.