Read & study

The source library.

Explore early cities, languages, religion, Kabbalah, alchemy, philosophy, human origins, and disputed history. Open a guide, follow its sources, and keep the next question in view.

This collection contains published introductions to the growing knowledge base. Each guide links its sources; traditions and open hypotheses retain their context.

6 of 96 source guides

Mesopotamia c. 1800 BCE

Plimpton 322: a Babylonian table and its interpreters.

Meet a clay tablet from around 1800 BCE whose columns of numbers have been read in several ways. Separate the object from the interpretations.

Thebes, Upper Egypt 1550 BCE

The Rhind Papyrus: a scribe's handbook of problems.

Open the British Museum's record for the Rhind Mathematical Papyrus, a collection of 84 worked problems, and learn why an object's date and its text's origin are different questions.

Zhangjiashan, Hubei, China Western Han, tomb closed by 186 BCE

Writings on Reckoning: an excavated text beside a transmitted classic.

Compare the Suan shu shu, a mathematical manuscript on bamboo strips from a Han tomb, with the transmitted Nine Chapters, and learn how excavated witnesses test a textual tradition.

Kouyunjik, Nineveh, Iraq 7th century BCE

K.2069: a reciprocal table from the library at Nineveh.

A seventh-century tablet from Nineveh lists reciprocals for sexagesimal arithmetic. Learn why the date of an artifact is not the date of the mathematics on it.

Syracuse, Sicily 287–212 BCE

Archimedes: what survives of his works.

The treatises of Archimedes reach us through manuscripts made a thousand years after his death. Learn to keep an author's lifetime, a text's composition, and a copy's date apart.

Mesopotamia (provenance unknown) Old Babylonian period

YBC 7289: the square root of two on a school tablet.

A small round clay tablet from the Old Babylonian period shows a square with its diagonals and a number close to the square root of two. Read the numbers as a scribe would.