Experts called in to examine a rocks unearthed during a garden makeover were convinced they had found a unique Viking settlement.
The area has strong links to Norse culture
But they were left red-faced after months of excavation work found nothing more than an old garden patio.
Huge slabs uncovered in Marion Garry's garden in Buckhaven, Fife, had experts convinced they had found evidence of an early Viking village.
They were left disappointed when the structure was dated to the 1940s.
'Tell-tale signs ignored'
Douglas Speirs, chief archaeologist at Fife Council, told BBC Radio Scotland's Fred MacAulay programme that it was an "easy mistake to make."
He explained: "This project first began in the summer when some private residents in Buckhaven began excavating in their back garden.
"During this work they uncovered a series of very interesting features that we thought may well represent a significant archaeological find.
"Over the course of the following months, we engaged in a series of excavations only to find out that what we were digging up was in fact a 1940s patio.
"In our defence, from the limited information we had at first, it did seem a reasonable and plausible situation that this might be a site of some antiquity in so far as it was situated on a raised beach right next to the sea and had all the hallmarks of ancient building techniques."
Mr Speirs admitted that his team mistakenly ignored the finds of a World War II child's gas mask and old television remote in their hunt for Viking evidence.
He said: "Buoyed up by the fact that we were digging for something of some significance, we kind of ignored these tell-tale signs. Looking back now, that probably wasn't the best approach.
"One of the things that really pushed us over the limit in this case is that the houses on site were built in 1939 and the chap next door - who has lived there since 1939 - was absolutely adamant that there has never been a patio in that back garden."
He added that his department would "be more careful" when examining any future sites of archaeological interest.
Marion Garry, 50, who called the team to her garden after watching a TV programme about hidden archaeological treasures in populated areas, said she now hoped to turn the unearthed patio into a garden feature.
She said: "It looks quite messy now but I think it will look pretty with flowers and plants growing around it."