A dust-covered “old press”, destined for a skip in Co Wexford, has turned out to be a rare 15th-century Flemish altarpiece valued at €100,000. The discovery was made by the parish priest of Piercetown (also known as Piercestown), a village between Wexford town and Rosslare.

But mystery surrounds how, and why, the work of art, created during the Northern Renaissance – which flourished in the Netherlands and Flanders more than 500 years ago – came to be in Co Wexford.

Fr John O’Reilly said the item came to light when an outbuilding in the parochial house’s ground was being cleared. He had planned to convert the disused garage into a parochial office. Workmen putting material into a skip came across what looked like “an old press or bathroom cabinet”.

The priest “told the lads to leave it to one side”.

Months later, he “took a closer look before throwing it out”. He noticed paintings on the doors of the cabinet, “discovered a face among all the grime”, and wondered: “Have I got another Caravaggio?” Then he “opened the doors and discovered the statues”.

The altarpiece is a triptych with painted door panels that open to reveal a central tableau of sculpted carvings depicting the lamentation of Christ.

Fr O’Reilly contacted a local antiques dealer, “who got excited”. Since the initial discovery, two years ago, he has been in contact with the National Gallery, experts in the Netherlands and various fine-art auctioneers in Ireland and overseas.

Fr O’Reilly became parish priest in 2009 and his predecessor is deceased. He said there was no record of how the altarpiece ended up in the garage.

It will go under the hammer next month at Sheppard’s auctioneers in Durrow, Co Laois, with an estimate of €80,000- €120,000. Fr O’Reilly said the proceeds would be used to benefit the parish, including a project to renovate the sacristy for use as an oratory.

Sheppard’s said the altarpiece had possibly been made by “a follower of Dieric Bouts”, a leading artist of the period and one of the so-called Flemish Primitives.