The Frome Hoard, the largest collection of Roman coins unearthed in a single container, is to go on display to the public for the first time.
The collection of 52,503 silver and copper alloy coins, unearthed by metal detectorist Dave Crisp in April last year near the Somerset town that gives the hoard its name, is to go on show at the Museum of Somerset, in Taunton.
Stephen Minnitt, Somerset County Council's head of museums, hailed the "highly important find" and said it was a coup for the museum to obtain the coins.
"It's a very good news story in that he (Mr Crisp) reported his discovery, it was properly excavated and as a consequence we know far more about it than would otherwise have been the case," Mr Minnitt said.
"The reason it was buried remains something of a mystery. Usually you tend to think of coin hoards being buried for safety in the times before there were banks, which more often than not is the case, and those that are found today are the ones that were not recovered, presumably because the person that owned them, for whatever reason, had some sort of misfortune and didn't pick them up.
"In this case, though, the volume of coins in this very rounded pot - they weigh 160kg - has led to the suggestion that they may well represent a votive offering of some sort. Precisely what we don't know, but that's the thinking at the present time."
The 3rd Century AD coins, with their urn, are one of the prize exhibits of the museum, which has undergone a £6.93 million revamp. Other antiquities on display include the Low Ham mosaic, one of the country's finest surviving Roman floors.
Some of the coins have been completely cleaned to show what they may have looked like at the time they were buried, while others have been left in a condition closer to the way they looked when excavated.
The haul, valued at £320,250, was bought by the museum in March thanks to a grant of almost £300,000 from the National Heritage Memorial Fund.
An intensive fundraising campaign for the hoard, which contains 52,503 coins dating between AD253 and AD293, also benefited from a grant of more than £50,000 from the Art Fund, donations from various organisations and money raised by the public.