Why is Easter so late this year? Explaining how we date Easter Sunday

Dating Easter is confusing, it's based on out-dated calendars, ancient ties with Judaism and a big meeting of bishops in the 4th century: better strap in.

This year Easter Sunday will fall on the 20th of April, but the Christian holiday can come anywhere between the 22nd of March and the 25th of April - why is it so changeable?

The answer is all to do with the close historical and theological ties between Christianity and Judaism. It’s worth remembering also that Jesus and all of his apostles were Jewish, and that it was not until the First Council of Nicaea in 325 AD that a doctrine that we now recognize as definitively ‘Christian’ was established.

It was also during this meeting in the third century that the Church fathers settled the date of Easter, the festival that celebrates the resurrection of Christ after his crucifixion. They decreed that it should fall on the first Sunday after the Paschal Full Moon, an ecumenical full moon (aka, not always based on astronomy) that is the first after the March equinox (usually 20 March, but according to the Church it's 21 March).

This decision was made to ensure sure that Easter would always be celebrated after the Jewish festival of Passover, because although biblical calendars are never the most rigorous, it's clear that the death, birth and resurrection of Jesus all happened after this feast.

Passover is a Jewish festival celebrating the freeing of the Israelites from Egyptian slavery and it’s often thought that the Last Supper– the final meal Jesus took with the apostles – was a Passover Seder.

A 16th century depiction of the Last Supper which Mark records as the “first day of Unleavened Bread, when they sacrificed the Passover lamb.”

Read more: What is Passover?

At this point things get a little trickier. Because the early Christian fathers did not want to explicitly tie the date of a Christian festival to a Jewish one, they used complex formula to calculate the dates of future Easters by deciding in advance when the Paschal Full Moon would be.

Unfortunately, this meant that the Paschal Full Moon does not always correspond with the astronomical full moon (presumably due to mistakes in the calculations) and the two dates can vary by as much as two days.

Although this sounds like an awful mess, in practice this means that Easter usually does fall on the first Sunday after the astronomical full moon and always after Passover. The Church just took the long way round in terms of justifying their dates.

However, we're not done yet with all this confusion as the date of Easter varies even within Christianity – with the Orthodox Church (the section of the Church based primarily in Eastern Europe) making their calculations of Easter using the Julian rather than the Gregorian calendar.

Explaining the differences between the two calendars would be an article in itself but to keep it short - the Julian Calendar is less accurate than the Georgian. The Julian date of 21 March (the date of the March equinox - by which the date of the Paschal Full Moon is calculated) corresponds with 3 April in the Gregorian calendar, and therefore Orthodox celebrations of Easter can fall anywhere between 4 April and 8 May.

Thankfully this year there's no variation - both Easters will be celebrated on 20 April.

Start your day with The Independent, sign up for daily news emails
Voices
There will be a chance to bid for a rare example of the SAS Diary, collated by a former member of the regiment in the aftermath of World War II but only published – in a limited run of just 5,000 – in 2011
charity appealTime is running out to secure your favourite lot as our auction closes at 2pm tomorrow
Arts and Entertainment
Caroline Flack became the tenth winner of Strictly Come Dancing
tvReview: 'Absolutely phenomenal' Xtra Factor presenter wins Strictly Come Dancing final
Life and Style
A still from the 1939 film version of Margaret Mitchell's 'Gone with the Wind'
life
Arts and Entertainment
J Jefferson Farjeon at home in 1953
booksBooksellers say readers are turning away from modern thrillers and back to golden age of crime writing
PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksA year of political gossip, levity and intrigue from the sharpest pen in Westminster
Sport
Amir Khan is engaged in a broader battle than attempting to win a fight with Floyd Mayweather
boxing Exclusive: Amir Khan reveals plans to travel to Pakistan
News
Stacey Dooley was the only woman to be nominated in last month’s Grierson awards
mediaClare Balding and Davina McCall among those overlooked for Grierson awards
Voices
Joseph Kynaston Reeves arguing with Russell Brand outside the RBS’s London offices on Friday
voicesDJ Taylor: The great tradition of St Paul and Zola reached its nadir with a worker's rant to Russell Brand
News
Twitchers see things differently, depending on their gender
scienceNew study shows that birdwatching men have a lot in common with their feathered friends...
News
i100
News
Xander van der Burgt, at the Royal Botanic Gardens, Kew
scienceA Kew Gardens botanist has found 25 new large tree species - and he's sure there are more out there
Arts and Entertainment
British actor Idris Elba is also a DJ and rapper who played Ibiza last summer
film
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Finance Director

£65000 - £80000 per annum: Recruitment Genius: Finance Director required to jo...

Recruitment Genius: Medico-Legal Assistant

£15000 - £25000 per annum: Recruitment Genius: This is a unique opportunity fo...

Ashdown Group: (PHP / Python) - Global Media firm

£50000 per annum + 26 days holiday,pension: Ashdown Group: A highly successful...

The Jenrick Group: Quality Inspector

£27000 per annum + pension + holidays: The Jenrick Group: A Quality Technician...

Day In a Page

The week Hollywood got scared and had to grow up a bit

The week Hollywood got scared and had to grow up a bit

Sony suffered a chorus of disapproval after it withdrew 'The Interview', but it's not too late for it to take a stand, says Joan Smith
From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?

Panto dames: before and after

From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?
Thirties murder mystery novel is surprise runaway Christmas hit

Thirties murder mystery novel is surprise runaway Christmas hit

Booksellers say readers are turning away from dark modern thrillers and back to the golden age of crime writing
Anne-Marie Huby: 'Charities deserve the best,' says founder of JustGiving

Anne-Marie Huby: 'Charities deserve the best'

Ten million of us have used the JustGiving website to donate to good causes. Its co-founder says that being dynamic is as important as being kind
The botanist who hunts for giant trees at Kew Gardens

The man who hunts giants

A Kew Gardens botanist has found 25 new large tree species - and he's sure there are more out there
The 12 ways of Christmas: Spare a thought for those who will be working to keep others safe during the festive season

The 12 ways of Christmas

We speak to a dozen people who will be working to keep others safe, happy and healthy over the holidays
Birdwatching men have a lot in common with their feathered friends, new study shows

The male exhibits strange behaviour

A new study shows that birdwatching men have a lot in common with their feathered friends...
Diaries of Evelyn Waugh, Virginia Woolf and Noël Coward reveal how they coped with the December blues

Famous diaries: Christmas week in history

Noël Coward parties into the night, Alan Clark bemoans the cost of servants, Evelyn Waugh ponders his drinking…
From noble to narky, the fall of the open letter

From noble to narky, the fall of the open letter

The great tradition of St Paul and Zola reached its nadir with a hungry worker's rant to Russell Brand, says DJ Taylor
A Christmas ghost story by Alison Moore: A prodigal daughter has a breakthrough

A Christmas ghost story by Alison Moore

The story was published earlier this month in 'Poor Souls' Light: Seven Curious Tales'
Marian Keyes: The author on her pre-approved Christmas, true love's parking implications and living in the moment

Marian Keyes

The author on her pre-approved Christmas, true love's parking implications and living in the moment
Bill Granger recipes: Our chef creates an Italian-inspired fish feast for Christmas Eve

Bill Granger's Christmas Eve fish feast

Bill's Italian friends introduced him to the Roman Catholic custom of a lavish fish supper on Christmas Eve. Here, he gives the tradition his own spin…
Liverpool vs Arsenal: Brendan Rodgers is fighting for his reputation

Rodgers fights for his reputation

Liverpool manager tries to stay on his feet despite waves of criticism
Amir Khan: 'The Taliban can threaten me but I must speak out... innocent kids, killed over nothing. It’s sick in the mind'

Amir Khan attacks the Taliban

'They can threaten me but I must speak out... innocent kids, killed over nothing. It’s sick in the mind'
Michael Calvin: Sepp Blatter is my man of the year in sport. Bring on 2015, quick

Michael Calvin's Last Word

Sepp Blatter is my man of the year in sport. Bring on 2015, quick