The legacy of writing

Mesopotamians were proud of their cities and remembered destroyed ones in poetry. The Epic of Gilgamesh, written on twelve tablets, tells of a king of Uruk who, after the death of his heroic friend, went in search of the secret of immortality. He failed and came home. There he comforted himself by walking along the city wall of Uruk and admiring its fired-brick foundations. Unlike a tribal hero, he took comfort not in his sons outliving him but in the city his people had built.

Stories can be passed on by word of mouth, but science needs written texts that later scholars can read and build on. Mesopotamia's greatest legacy is its mathematics and time-reckoning:

• Tablets from about 1800 BCE contain tables of multiplication and division, squares and square roots, and compound interest.
• Their value for the square root of 2 was 1.41421296, very close to the correct 1.41421356.
• Students solved practical problems, such as working out the volume of water covering a field.

Our everyday measures of time come from Mesopotamia: 12 months in a year (following the moon), four weeks in a month, 24 hours in a day and 60 minutes in an hour. Mesopotamians also recorded the dates of solar and lunar eclipses and the positions of stars and constellations.

None of this would have been possible without writing and schools, where students copied older tablets and some boys were trained to be scholars who built on earlier work, not just record-keepers.

An early library. The Assyrians of the north built an empire (at its height 720 to 610 BCE) reaching as far as Egypt. Their last great king, Assurbanipal (668 to 627 BCE), admired the southern culture of Babylonia and collected a library at Nineveh:

• He sent scribes south to find old tablets on history, epics, omens, astrology, hymns and poems.
• Although Sumerian stopped being spoken around 1800 BCE, it was still taught in schools with word lists and two-language tablets, so very old tablets could still be read.
• Texts were copied with the copier's name and date, and catalogued: a basket of tablets carried a clay label saying what they were about.
• The library held about 1,000 texts, some 30,000 tablets, arranged by subject.

An early archaeologist. Babylon became the greatest city of the world, over 850 hectares with a triple wall and a ziggurat (stepped tower). Its last independent ruler, Nabonidus, studied an ancient stele to learn how a high priestess had once been dressed, and dressed his daughter that way for her consecration. When his men brought him a broken statue of Sargon, king of Akkad (about 2370 BCE), he had skilled craftsmen repair it. He treated the remains of the past with the care of an archaeologist.