It is a very familiar image.
It is not a very big picture - indeed it is so famous that when you see it close up it is surprising just how small it is.
The National Gallery website describes it thus.
This work is a portrait of Giovanni di Nicolao Arnolfini and his wife, but is not intended as a record of their wedding. His wife is not pregnant, as is often thought, but holding up her full-skirted dress in the contemporary fashion. Arnolfini was a member of a merchant family from Lucca living in Bruges. The couple are shown in a well-appointed interior.
The ornate Latin signature translates as 'Jan van Eyck was here 1434'. The similarity to modern graffiti is not accidental. Van Eyck often inscribed his pictures in a witty way. The mirror reflects two figures in the doorway.
If ever there was an example of understatement, it is that description from the National Gallery.
First of all consider the year it was painted. Yes - 1434. Henry VI was on the throne in England (we were still to have the whole Edward and Elizabeth Woodville, Richard III, Princes in the Tower and Battle of Bosworth thing - that was all in the future.) And the Mona Lisa was not going to be painted for another 70 odd years.
But in Northern Europe this Jan van Eyck chappie was re-writing art history.
Now, I am not an art historian - oh deary me no (I wish I was). Instead I am a bit if a fan of Waldemar Januszczak, an art critic and rather exuberant television presenter who, along with Andrew Graham Dixon, has a knack of making art just come alive.
And Mr Januszczak has just started to present a new program on BBC4 called Renaissance Unchained. I am hooked!
Which brings me back to the Arnolfinis.
So here's the thing, and we have good old Waldemar to thank for this. It's all about the clothes (well OK and the mirror too and the general genius of the whole piece) but for now it's all about the clothes.
Mr Arnolfini was Italian but he lived (or at least was based) in Bruges, because Bruges was the centre of the cloth trade.
He is wearing a purple tunic. Now, purple was a very expensive colour. But get this. His tunic is lined with fur. And his wife's green wool dress ( the wool could have come from England though was likely as not woven in Europe) that was lined with the pale fur from the belly of 2000 (2000 I tell you) red squirrels!
Now, we could get all indignant about the plight of the Red Squirrel but let's remember that the grey squirrel did not exist in Europe in those times. I share this gem of information just to give you a clue to how very wealthy Mr Arnolfini was, and how cold it must have been in rich merchants houses in Northern Europe in the 1430s.
But, if you are in London, I urge you to go and have a look at this picture. It takes your breath away - it almost sends a shiver down the spine. And if you look closely in the mirror you can see the artist painting the couple.
Failing that, watch the programme. If nothing else, those early flemish renaissance painters certainly knew how to paint a bit of cloth!