Cliff Massey, 86, was using a metal detector when he discovered a stash of 23 gold coins and 25 silver coins dating back more than 500 years.
He also made found a 15th-century gold ring with a blue sapphire.
Experts believe the treasure was buried in the ground around 1465 for safekeeping – but the items were never retrieved by their wealthy owner.
Each of the coins could be worth hundreds of pounds, according to experts.
Mr Massey, who has been metal detecting for 15 years, was walking through a field owned by a friend when his machine sprang into life.
He said: “It was amazing to find it all. I sat down and just laughed, I couldn’t believe it.
“People go out for years and years and never find anything and we have found all this.
“I don’t get as excited as I used to when I go out now because I know it can’t happen again!”
The coins date from the reigns of Edward III, Richard II, Henry VI – with three more pennies of uncertain rulers – and are believed to be from the same deposit in which someone buried or lost them after 1465.
Mr Massey was searching a field in Bronington, near Wrexham, North Wales, belonging to friend Ifor Edwards, 58, when he made the discovery.