It was the dress which had people's minds confounded and had the internet firmly in two camps - white and gold or blue and black.
And just as those rifts have healed, science has now explained why that dress was so divisive.
Researchers from New York University say it depends on how you thought the dress was illuminated.
Neuroscientist Pascal Wallisch says those who saw the overexposed photo as being taken in shadow would have likely seen the garment as white and gold, whereas those who thought it was lit by artificial light would have seen it as blue and black.
For the record, the dress was actually blue and black. While the dress came in a number of other colours, including red and pink, none of them were white and gold.
"Shadows are blue, so we mentally subtract the blue light in order to view the image, which then appears in bright colors - gold and white," Mr Wallisch says.
"However, artificial light tends to be yellowish, so if we see it brightened in this fashion, we factor out this colour, leaving us with a dress that we see as black and blue."
The findings were based on an online study of more than 13,000 participants and have been published in Journal of Vision.
Of those who thought the dress was taken in shadow, 80 percent thought the dress was white and gold. Around half who thought the dress was illuminated thought it was white and gold.
Exposure to daylight could also explain the two camps.
Those who identified as earlier risers and therefore more exposed to sunlight, were significantly more likely to see the dress as white and gold than night owls, whose worlds are dominated by artificial light.
"This suggests that whatever kind of light one is typically exposed to influences how one perceives colour," Mr Wallisch says.
Demographics, gender and age have very little to do with how people perceived the dress.
Mr Wallisch says the findings offer a new view on the question - 'Is the colour you see, the same colour I see?'
"The answer - based on this research - is 'not necessarily'.'"