File:The Library of Flavius Pantaenus in Athens. Around 100 A.D.jpg

English: The Library of Pantainos is located on the east side of the Panathenaic Way, south of the Stoa of Attalus. It consists of a large square room and a paved courtyard, surrounded by three stoas with shops behind their colonnades. The north stoa runs eastward, along the south side of a marble street that led in Roman times from the Agora to the Doric gateway of the market of Caesar and Augustus, also known as the Roman Agora.

According to its inscribed marble lintel block the library was dedicated to Athena Archegetis, the emperor Trajan and the Athenian people in the years around 100 A.D., by Titus Flavius Pantaenus who describes himself as a priest of the philosophical muses as well as the son of the head of a philosophical school. The library rules, much as they would be today, are preserved in another inscription found in the building: “No book is to be taken out since we have sworn an oath. The library is to be open from the first hour until the sixth.” Trajan seems actually to have been worshipped in the building as part as parts of his statue were found in the ruins. The remains of the library reinforce the opinion that we have not only the “library of Pantaenus” here, but also one of the famed philosophical schools of Athens. The north and west stoas were destroyed by the Herulians in 267 A.D. In the 5th century A.D. the east stoa was rebuilt with the addition of a second storey for the eastern two-thirds of its length. The rooms at ground level behind the colonnade were also refurnished, to serve as a basement suite for the principal rooms on the floor above, which had a small peristyle court, an apsidal room and provisions for bathing. This large building was probably an official residence.

Source: Inscription at the archaeological site.