Of all people, the Christian Coptic Pope is the culprit who ordered the demolition of the great library in the 4th century CE. The Muslim Empire and scholars somehow managed to scrambled majority of the Greek civilization learning and books of what have been left after the destruction, and also significantly add their own knowledge contributions. The effort resulted in the two greatest centers of ancient texts in the world by the 11th century CE.
Baghdad center was ransacked to the ashes, and majority of the stored books and manuscripts demolished. The only surviving secondary or lesser center of the two was Toledo. Toledo fell to the Spaniard in 11th century. Benedict the abbot who in charged of more than 600 monastery has ordered the clergy to literally copy and also translate books and scriptures from the center in Toledo. In Toledo there existed original Arabic books on the new knowledge, Arabic translations of Greek books and scriptures that otherwise have been lost forever, and perhaps many copies of the original books of Greek civilization but we probably never knew the exact composition since this happened about a thousand years back. These copies of the books and manuscripts were ordered to be kept in these many monasteries, and the books and manuscripts remained there for centuries. If you think only a few works (less than five) of the ancient Greek works that were preserved during the time due to the Muslim empire and scholars efforts, I really want to know what are the things that you are smoking at the moment?