Around 640 BCE, the Assyrian king Ashurbanipal gathered tens of thousands of clay tablets in his palace at Nineveh, in what is now northern Iraq. When enemies sacked the city in 612 BCE, the palace burned, and the fire baked the clay hard. The tablets survived for more than two thousand years, and among them archaeologists found copies of the Epic of Gilgamesh. The library of Alexandria, the most famous library of the ancient world, would have the opposite fate. Its books were written on materials that fire destroys and time rots, and almost nothing of the collection itself survives.

Writing before the library

Libraries existed long before Alexandria. Temples in Egypt and Mesopotamia kept religious and administrative records, and Ashurbanipal's collection was a deliberate attempt to gather knowledge in one place. What made Alexandria different was its ambition: to collect books from every people and in every field, and to place scholars beside them.

Greek books of this period were scrolls made of papyrus, a writing material produced from a reed that grew in the marshes of the Nile. Strips of the reed's pith were laid in crossing layers, pressed together and dried into sheets, which were glued end to end into a roll. A single scroll might hold one book of Homer or one play. A long work therefore filled many scrolls, which is why ancient counts of a library's “books” are hard to compare with modern ones. Papyrus has one great weakness: it decays in damp air, so scrolls had to be copied again every few generations or be lost.

Aristotle and the habit of collecting

In Athens, the philosopher Aristotle (384 to 322 BCE) built one of the first large private collections of books, and the ancient geographer Strabo later called him the first person known to have collected books and taught the kings of Egypt how to arrange a library. Strabo was writing three centuries later and may have exaggerated. But Aristotle's school, the Lyceum, did model something new: a community of researchers who gathered information, sorted it and wrote it up, from the constitutions of Greek cities to the habits of sea creatures.

A new city

In 331 BCE Alexander the Great founded Alexandria on the Mediterranean coast of Egypt, at the western edge of the Nile Delta. He had been taught as a boy by Aristotle, and he went on to conquer an empire stretching from Greece to the borders of India. He died in Babylon in 323 BCE, still in his early thirties, and his generals divided his empire among themselves.

Egypt went to Ptolemy, a Macedonian officer who had served beside Alexander since childhood. Ptolemy seized Alexander's body on its way back to Macedonia and buried it in Egypt, a sign that he meant to claim Alexander's prestige. In 305 BCE he declared himself king. He and his descendants, the Ptolemaic dynasty, ruled Egypt for nearly three hundred years, until the death of its last ruler, Cleopatra VII, in 30 BCE.

Why a king would want a library

The Ptolemies were Greek-speaking foreigners ruling an ancient land. A great library served them in several ways. It made Alexandria a cultural capital that could rival Athens. It attracted talented people from across the Greek world. And it advertised the dynasty as heirs of Alexander and patrons of learning, a kind of soft power that rival kings in Syria and Pergamon soon tried to copy.

Historians stress that we know less about the library than its fame suggests. No ancient description of the building survives, and no archaeologist has identified its remains with certainty. Much of what we “know” comes from writers living centuries later, some of them repeating stories. This course will keep separating what the evidence shows from what legend has added, because the story of the library is also a lesson in how history is pieced together.

Worked example: counting scrolls

Suppose an ancient writer says a library held 400,000 books. What does that number mean? Work it through.

• What is a “book”? In Greek usage, a book was usually one scroll. Homer's Iliad is divided into 24 books, so a complete copy might fill 24 scrolls. A count of scrolls is not a count of titles.
• Duplicates. A library might hold several copies of popular works, and scrolls could contain several short works or only part of a long one.
• Who is counting? Ask whether the writer saw the library, heard about it, or copied the figure from an earlier author. A round number reported centuries later deserves caution.
• What else do we know? Compare the number with what is known about the cost of papyrus, the speed of copying and the size of other ancient collections.

By the end of this check, “400,000 books” might mean anything from a few tens of thousands of distinct works to a figure that was simply inflated by later admirers. That is not a reason to dismiss the library. It is a reason to read the sources carefully, the same habit any citizen needs when a confident number appears in the news.