New research has revealed how a True Cross relic, said to be a fragment from the crucifixion of Jesus, came to be in a convent in Northern England.

An ornate reliquary case of silver gilt, precious stones and crystal was completed for the religious artefact in 1870, and it has been kept at the Bar Convent in York for centuries.

A Latin inscription says it was given to an English knight from the Shirley family by Arnulphus, Patriarch of Jerusalem, for his “valour” during the Crusades.

Special collections manager Dr Hannah Thomas with a True Cross relicSpecial collections manager Dr Hannah Thomas with a True Cross relic (Danny Lawson/PA)

The convent wanted to show the relic in the 1860s for public veneration so it needed it to be authenticated by high-ranking Church officials.

Studies of historical documents show it likely changed hands from the Shirley family in the 16th century, before coming into the family of a Jesuit priest who gave it to the convent.

Dr Hannah Thomas, the first lay person to look after the convent’s collections, said: “We are thrilled to be able to enrich our knowledge of this piece, which has been so well protected and admired for centuries.

“It is a centrepiece of our collections and remains an object of contemplation with both religious and historic significance.

“We considered Easter, and the anniversary of when it was first authorised for veneration, to be the most appropriate time to share this research and to highlight this special object.”

The relic goes on display at The Bar Convent, England’s oldest convent still in use, from April 2.