Mouseion is a cult center built for the cultivation and worship of the Muses. Originally, it was an open portico with an altar, but without a regular temple. Demetrius of Phalero advised Soter I to build the Library muses and the Mouseion. It was situated in the royal quarter. It consisted of a cloister, an arcade and a large house. Members of the Mouseion performed religious activities and engaged in teaching or in scientific research.
The library of Alexandria was established in the reign of Ptolemy II. The idea and the first stages of planning of the library were due Ptolemy I. The royal library started by Ptolemy II.
The daughter library was built during the reign of Ptolemy III and attached to the temple of Serapis.
Ptolemy III ordered that all books found in ships should be seized and copied and the copies to be given to their owners. Books acquired special labels (from the ships).
The bibliomania of Ptolemy III drove him to trick the Athenians by borrowing from them their official copies and deposited the sum of fifteen talents as security for their safe return. However, he kept the originals and sent copies. Moreover, he sent agents to Athens and Rhodes to buy books.
The library began to decline in the later part of second century B.C.

Alexandria’s Great Library and Mouseion were founded to house books and gather scholars in about 295 B.C, when Ptolemy I appointed Demetrius of Phalero, a former pupil of Aristotle to take charge of the twin institutions. The earliest reports assert that Demetrius had a large budget and a permission from the king to collect all the books in the world.
The goal was to collect half a million manuscripts, and successive Ptolemaic kings were determined in their efforts to acquire them. Any books not in stock in the library were confiscated or copied from passengers who sailed into Alexandria.
It was conceived as a universal library that ‘had to contain the writings of all nations’. Foremost among non-Greek writings kept in the library were the Egyptian ‘sacred records’ by the Egyptian priest Manetho, and a history of Babylonia by Berossus. Buddhist writings were also donated to the library by the Indian King Asoka. A translation of the first five books of the Old Testament into Greek was made in Alexandria, ensuring the spread of biblical knowledge in the Hellenistic world. Within half a century, the Great Library proved too small for the wealth of books acquired, so Ptolemy III decided to attach a branch known as the Daughter Library to the newly rebuilt Sarapeion.
The infamous destruction by fire of the Library of Alexandria, with the consequent loss of the most complete collection of ancient literature ever assembled, has been a point of heated debate for centuries.
The prime suspect in destruction of the Library of Alexandria is Julius Caesar. For his own safety he had his men set fire to the Egyptian ships, but the fire got out of control and spread to the parts of the city nearest the shore, which included warehouses, depots and some arsenals.
Another event that is related to the destruction of the Library of Alexandria occurred in 391 AD, when Emperor Theodosius declared all forms of paganism illegal and proclaimed that it needs to be destroyed. Patriarch Theophilus of Alexandria took it upon himself to carry out the order and burned down any temple that did not worship Christ, including the Serapeum. It is unknown if the vast collection of books and scrolls from the Library of Alexandria were inside and if they were destroyed by the blaze.
Another event that is related to the destruction of the Library of Alexandria occurred in 640 AD, when the Moslems took the city of Alexandria. Upon learning of “a great library containing all the knowledge of the world” the conquering general supposedly asked Caliph Omar for instructions. The Caliph has been quoted as saying of the Library’s holdings, “they will either contradict the Koran, in which case they are heresy, or they will agree with it, so they are superfluous.” So, allegedly, all the texts were destroyed by using them as tinder for the bathhouses of the city. Even then it was said to have taken six months to burn all the documents.
The real tragedy of course is not the uncertainty of knowing who to blame for the Library’s destruction but that so much of ancient history, literature and learning was lost forever.