Surah 18. Al-Kahf, Ayah 25

This obviously connects with the "idle guesses" mentioned in the first paragraph of verse {22} above - guesses refuted by the subsequent statements, "My Sustainer knows best how many they were" in verse {22}, and "God knows best how long they remained [there]" in verse {26}. This was, in particular, the view of 'Abd Allah ibn Mas'ud, whose copy of the Qur'an is said to have contained the words, "And they [i.e., some people] said, 'They remained...'," etc. (which was probably a marginal, explanatory remark added by Ibn Mas'ud), as well as of Qatadah and of Matar al-Warraq (Tabari, Zamakhshari and Ibn Kathir). My interpolation, at the beginning of the verse, of the words "some people asserted" is based on the word qalu ("they said") used by Ibn Mas'ud in his marginal note.

 Three hundred years in the Gregorian calendar equal three hundred and nine years in the Islamic lunar calendar.

This verse should be read with the next verse. In the floating oral tradition the duration of time in the Cave was given differently in different versions. When the tradition was reduced to writing, some Christian writers (e.g., Simeon Metaphrastes) named 372 years, some less. In round numbers 300 years in the solar Calendar would amount to 309 in the lunar Calendar. But the next verse points out that all these are mere conjectures: the number is known to Allah alone. The authority on which Gibbon relies mentions two definite reigns, that of Decius (249-251 A.D.) and that of Theodosius 11 (408-450 A.D.). Taking 250 and 450, we get an interval of 200 years. But the point of the story does not lie in the name of any given Emperor, but in the fact that the beginning of the period coincided with an Emperor who persecuted: the Emperor's name at the end of the period may be taken as approximately correct, because the story was recorded within two generations afterwards. One of the worst Emperors to persecute the Christians was Nero who reigned from 54 to 68. If we took the end of his reign (A.D. 68) as the initial point, and (say) 440 A.D. as the final point, we get the 372 years of Simeon Metaphrastes. But none of these writers knew any more than we do. Our best course is to follow the Quranic injunction, "Say, Allah knows best how long they stayed" (xviii. 26). There is also a rebuke implied: 'do not imitate these men who love mischievous controversies!' After all, we are given the narrative more as a parable than as a story.