DraftWritten with AI help from the sources it cites, and not yet read by a human editor.
At a glance
Curriculum expectations
F1.1— describe ways in which common celebrations and commemorations associated with various religions and/or belief traditions are linked to concepts of timeF1.2— identify and explain the significance of historical events and natural cycles that are commemorated in various religions and belief traditions […]
Brief
This lesson asks you to describe how celebrations are linked to ideas of time, and to identify and explain the historical events and natural cycles that a tradition commemorates. The museum offers the Islamic lunar calendar, which is tied to the sighting of the moon and counts from a journey; your class adds the calendars of the other traditions. 1
What does a community count, and from where?
Find in each source what sets the start of a month or a year: something seen in the sky, or something remembered from the past. Note which of the festivals and rites you have met this term depend on that start.
Go deeper
Ibn al-Athir's al-Kamil says that in the year 16 Umar ibn al-Khattab (may God be pleased with him) set the dating of the calendar on the advice of Ali ibn Abi Talib (may God be pleased with him), and that the start of the Islamic calendar was made the Prophet ﷺ's migration from Mecca to Medina 2. In the chapter on dating in Sahih al-Bukhari, Sahl ibn Sa'd says that they did not count from the Prophet's mission or from his death, but only from his arrival in Medina 3. The Encyclopaedia of Islam adds that the era does not begin on the day Muhammad reached Medina, but on the first day of the lunar year in which this happened, reckoned to coincide with 16 July 622 4. So the three sources answer the question "counted from where?" with a remembered event, not with something seen in the sky.
Two views
How is a month established by the crescent? The Kuwaiti encyclopaedia of jurisprudence says Ramadan is established by sighting its crescent, or by completing Sha'ban to thirty days when sighting fails. It says the jurists differ on the number of witnesses: the Hanafis, Shafi'is and Hanbalis accept one just witness, the Malikis require two. It adds that the jurists agree the end of Ramadan, the crescent of Shawwal, needs two witnesses 5 6 7 8. The Encyclopaedia of Islam, on the Shafi'i account, says the general obligation begins on 1 Ramadan after thirty days of Sha'ban, or after twenty-nine if the judge has accepted the testimony of one trustworthy person that he saw the new moon 9. The museum prefers no school.
Often misunderstood
It is easy to suppose year 1 began on the day the Prophet reached Medina. The Encyclopaedia of Islam says the era does not begin on that day but on the first day of the lunar year in which it happened, and that this result assumes that no intercalary months occurred after the Hijra, which is by no means certain 4. In its article on the Farewell Pilgrimage it names the abolition of intercalation and a purely lunar year among the arrangements made on that occasion, and says that because the lunar calendar has no intercalary month, the pilgrimage falls ten or eleven days earlier each year and runs through the whole cycle of the seasons in thirty-two to thirty-three years 10 11.
How do we know?
The report of the dating in the year 16 comes from Ibn al-Athir's al-Kamil, a history 2. The record of the Hijri calendar says the reports differ over whether the decision followed a consultation with the Companions and over which year it was, and that this needs a second source before it can be treated as established. The definition of the calendar as a lunar one counted from the Hijra comes from al-Suyuti's Tarikh al-Khulafa 12. The record of the Hijra says historians debate the exact sequence of events, so its dates are marked as traditional 13. The conversion of dates from Hijri to Gregorian is, in the museum's words, a derived calculation, not taken from a source.
Think about it
These sources give two starting points: a sighting that begins each month, and a remembered event that begins the count of years. Which of the two would a community need to agree on more often, and what in the sources shows how disagreement about each is settled?
Into the museum
- The crescent: its definition and the times the crescents were made, in the Kuwaiti encyclopaedia.
- The Hijri calendar: what it fixes, and the disagreement over choosing the Hijra as its start.
- Umar's decree: the report for the year 16 in Ibn al-Athir.
- The Hijra: the accounts, their differing dates and the encyclopaedia's article.
- Ramadan: how the month is established and how many witnesses the schools accept.
Try this
Read the crescent, the Hijri calendar and Umar's decree. Draw a short timeline with a moon cycle above it and the starting event below it, and label what each tells a community.
Sources
- Ontario Ministry of Education, The Ontario Curriculum: Social Sciences and Humanities
- al-Kamil fi'l-Tarikh of Ibn al-Athir , p. 351
- Sahih al-Bukhari , 3934
- Encyclopaedia of Islam, 2nd edition (Leiden: Brill, 1954–2008), 13 volumes , vol. 3 p. 387
- al-Mawsu'a al-Fiqhiyya al-Kuwaitiyya, Noor-Book copy (file named v3) , p.8986
- al-Mawsu'a al-Fiqhiyya al-Kuwaitiyya, Noor-Book copy (file named v3) , p.8987
- al-Mawsu'a al-Fiqhiyya al-Kuwaitiyya, Noor-Book copy (file named v3) , p.8988
- al-Mawsu'a al-Fiqhiyya al-Kuwaitiyya, Noor-Book copy (file named v3) , p.8989
- Encyclopaedia of Islam, 2nd edition (Leiden: Brill, 1954–2008), 13 volumes , vol. 9 p. 103
- Encyclopaedia of Islam, 2nd edition (Leiden: Brill, 1954–2008), 13 volumes , vol. 3 p. 42
- Encyclopaedia of Islam, 2nd edition (Leiden: Brill, 1954–2008), 13 volumes , vol. 3 p. 43
- Tarikh al-Khulafa — al-Suyuti (Dar al-Minhaj edition)
- Watt, Muhammad at Medina (1956)
Cite this page
islam.museum contributors. “Time told by the moon”. islam.museum, https://islam.museum/en/course/ca-on-g11-hrf3o-f-1/. CC BY-SA 4.0. Last updated 2026-11-13.
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