In ancient Greece, a country where science and philosophy were born, art reached its climax, theatre functioned as a school for people of all ages, it was natural that libraries should not only exist but also be very popular. All relevant information concerning this subject derives mainly from epigraphic sources, since ancient writers only sporadically refer to it. Several libraries existed in Athens. One according to Polybius the Eldest, dated to the years of Peisistratus, was transferred to Persia when Xerxes invaded Athens, while another one was that of Demetrius Phalereus. Pausanias gives an account of the rich library of Hadrian (132 AD), while the library of Pantainos (100 AD) is known to us from two inscriptions, the one also mentioning a library located in Piraeus. A library also existed in the Gymnasium of Ptolemy (181-145 BC). A number of libraries were located in various other religious and cultural centres besides Athens, such as Delphi, Epidaurus, where the library was dedicated to Asclepius, Delos, comprising the works of the poet Alcaeus, as well as on famous historic islands, such as Samos, Rhodes, Kos, Crete, Cyprus. Outside metropolitan Greece the libraries of Pergamon, Ephesus, Miletus, Halicarnassus, etc.. became especially renowned.