Dear Sister, Salams
They never slept for 300+ years. Some people thought so.
Here is a brief info. For details, please study Surah 18 at www.ourbeacon.com Library, THE QUR'AN ........
Surah 18. Al-Kahf – The Cave
[Author’s Note] This is the 18th Surah of the Qur’an. It has 110 verses. The Surah derives its name from the Cave in which some young men (probably seven of them) had taken shelter against persecution by the Roman Emperor Decius (who ruled between 249-251 CE). Decius (Daqianoos) being a pagan was known for his persecution of the Monotheistic Christians. They were true Unitarian followers of Jesus Christ, and they took refuge outside the town of Ephesus (Afsoos) in today’s Turkey. The 19th Century Archaeology has uncovered the ruins of the town just South of Izmir. Dwellers of the Cave, known as 'The Seven Sleepers' in history, have also been referred in this Surah as the owners of Ar-Raqeem - from Raqam meaning inscribing - Inscription. I understand that they held on to the Scripture, the Gospel of Jesus. The dogmas of Trinity, Blood Atonement, Divinity and Sonship of Jesus, all were canonized about 75 years after Decius at the Conference of Nicea under Emperor Constantine in 325 CE. So, the Gospel that these young men held on to, was much closer to the real teachings of Jesus. They were vanguards of truth, and not ascetics withdrawing from the responsibilities of the worldly life.
Al-Kahf is one of the most commonly misinterpreted Surahs of the Qur’an because of contradictory historical accounts, questionable Ahadith and the Biblical influence on the minds of many commentators. The Qur’an, as always, sifts out fabrications and expounds the truth. Tasreef (and some relevant history) help us understand this Surah. The Surah also gives us an important lesson that true revolutions begin in the hearts, and violent revolutions create only corruption, disorder and bloodshed in the land.