Wikipedia's first sentence called it “different from the solar-based gregorian calendar”. Today it says “based upon the cycle of the moon”.
Measured, not asserted. Every count, date and revision on this page was taken from Wikipedia's own history and checked against the live article. The words quoted are theirs.
Machine-checked against the full current article on 2026-08-03.
We saved snapshots of this article over twenty years; you are reading the 2025 one. Red dashes: removed from Wikipedia since.Pale dots: rewritten; the numbered note shows what it says now.Red text: written in or rewritten since the previous snapshot.1 tap a number or a side note to jump between them
The opening as it read in 2025
Holidays in Islam Eid celebration in Sholakia , Bangladesh . The largest Eid congregation . There are two main holidays in Islam that are celebrated by Muslims worldwide: Eid al-Fitr and Eid al-Adha . The timing of both holidays are set by the lunar Islamic calendar , which is based upon the cycle of the moon, and so is different from the more common, European, solar-based Gregorian calendar . Every year, the Gregorian dates of the Islamic holidays change. Both Eid al-Fitr and Eid al-Adha follow a period of 10 holy days or nights: the last 10 nights of Ramadan for Eid al-Fitr, and the first 10 days of Dhu al-Hijjah for Eid al-Adha. The Night of Power (Arabic: لیلة القدر, romanized : Laylat al-Qadr), one of the last 10 nights of Ramadan, is the holiest night of the year. Conversely, the Day of Arafah , the day before Eid al-Adha, is the holiest day of the Islamic year. There are a number of other days of note as well as festivals, some common to all Muslims, others specific to Shia Islam or branches thereof. Additionally, Friday is considered the holiest day of the week, and, in Islamic tradition, is considered a celebration in itself. Friday prayers (Juma) are congregational prayers held in mosques , and Muslims are encouraged to wear clean and refined clothes, perfume, and bathe. It is customary to eat special meals with family on this day.
This is Wikipedia's own text, saved in our repository. Their copy of it is revision 1294544760.
The opening as it stood in 2010
There are two main holidays in Islam , Eid Al-Fitr and Eid Al-Adha . The way that holidays are recognized can vary across cultures, as well as across sects of Islam, Sunni and Shia . Muslim holidays generally follow the lunar calendar , and thus move each year relative to the solar calendar .The Islamic calendar has 12 months and 354-355 days. Sunni and Shia lunar calendars do not always coincide: sometimes a Shia holiday and the same Sunni holiday occur on two different days, typically two successive ones. Islamic dates are based on a lunar calendar, and may vary by 1-2 days from what is predicted below .
Red text was written in or rewritten since the previous snapshot. Their copy is revision 368902612.
The opening as it stood in 2015 4 passages from the previous snapshot no longer appear
There are two official holidays in Islam : Eid Al-Fitr and Eid Al-Adha .Eid Al-Fitr is celebrated at the end of Ramadan (a month of fasting), and Muslims usually give zakat (charity) on the occasion.Eid Al-Adha is celebrated on the tenth day of Dhu al-Hijjah and lasts for four days, during which Muslims usually sacrifice a sheep and distribute its meat among family, friends, and the poor.Both holidays occur on dates in the Islamic (Hijri) calendar , which is lunar, and thus their dates in the Gregorian calendar , which is solar, change each year.The Gregorian calendar is based on the orbital period of the Earth's revolution around the Sun, approximately 365 1 ⁄ 4 days, while the Islamic calendar is based on the synodic period of the Moon's revolution around the Earth, approximately 29 1 ⁄ 2 days.The Islamic calendar alternates months of 29 and 30 days (which begin with the new moon).Twelve of these months constitute an Islamic year, which is 11 days shorter than the Gregorian year.
Red text was written in or rewritten since the previous snapshot. Their copy is revision 669326587.
The opening as it stood in 2020 4 passages from the previous snapshot no longer appear
There are two official holidays in Islam, Eid al-Fitr and Eid al-Adha . Both holidays occur on dates in the lunar Islamic calendar , which is different from the solar based Gregorian calendar , so they are observed on different Gregorian dates every year.There are a number of other days of note and festivals, some common to all Muslims, other specific to Shia Islam as a whole or branches thereof.Eid al-Fitr is celebrated at the end of Ramadan (a month of fasting during daylight hours), and Muslims may perform acts of zakat (charity) on the occasion, which begins after the new moon is sighted for the beginning of the month of Shawal .Celebration begins with prayers on the morning of 1 Shawal, followed by breakfast, and often celebratory meals throughout the day.Eid al-Adha is celebrated on the tenth day of Dhu al-Hijjah , when the Hajj pilgrimage takes place, and lasts for four days.Muslims may perform an act of zakat and friendship by slaughtering a sheep and distributing the meat to family, to friends, and to the poor.Muslims are also encouraged to be especially friendly and reach out to one another during this period.
Red text was written in or rewritten since the previous snapshot. Their copy is revision 965063863.
The opening as it stood on October 6, 2023 5 passages from the previous snapshot no longer appear
Holidays in Islam There are two official holidays in Islam , Eid al-Fitr and Eid al-Adha , which are celebrated by Muslims worldwide. Both holidays occur on dates in the lunar Islamic calendar , which is different from the solar-based Gregorian calendar , so they are observed on different Gregorian dates every year. There are a number of other days of note and festivals, some common to all Muslims, others specific to Shia Islam as a whole or branches thereof. Both Eid al-Fitr and Eid al-Adha follow a period of 10 holy days or nights: the last 10 nights of Ramadan (Eid al-Fitr), and the first 10 days of Dhu al-Hijjah (Eid al-Adha).The Night of Power , one of the last 10 nights of Ramadan, is the holiest night of the year.Conversely, the Day of Arafah , the day before Eid al-Adha, is the holiest day of the Islamic year.Additionally, Friday is considered the holiest day of the week, and in Islamic tradition, is considered a celebration in itself.Friday Prayers (Juma) are congregational prayers held in mosques, and Muslims are encouraged to wear clean and refined clothes, perfume, and bathe.It's customary to eat special meals with family on this day.
Red text was written in or rewritten since the previous snapshot. Their copy is revision 1178426310.
Today
Wikipedia's first sentence called it “different from the solar-based gregorian calendar”. Today it says “based upon the cycle of the moon”. Read the current article and compare.
2010
2015
2020
Oct '23
2025
Counts in the opening at each snapshot. Green: the word gained ground. Red: it was cut. Grey: no change.
What Wikipedia says this is
Every article opens by defining its subject. This one was redefined since October 7, and today's defining sentence is their current revision.
Then
different from the solar-based gregorian calendar
Now
based upon the cycle of the moon
Struck red text is no longer in the article; dotted amber text was rewritten. Every revision id links to Wikipedia's copy; the text shown is our own saved copy. Data: /data. Wikipedia text is CC BY-SA; quoted for the record; not affiliated with Wikipedia.