About 3,000 skeletons are to be reburied in an Anglo-Saxon ceremony at a North Lincolnshire church where they were discovered almost 30 years ago.
The church underwent a £600,000 refurbishment to house the remains
The ancient language will be used by the Reverend David Rowett at St Peters Church in Barton-upon-Humber to mark the return of the historic bones.
Unearthed between 1978 and 1984, the bones have been used by English Heritage to research diseases.
They are one of the largest collections found on a single site in England.
The collection, housed in a specially built bone repository called an ossuary to protect the remains, was re-dedicated to the ground on Monday ahead of the ceremony.
A spokesman for English Heritage said the service on Friday evening would be spoken in Anglo Saxon, as a mark of respect.
The research was done in partnership with the Church of England, which allowed the church to be reopened for the first time since 1972 for people to view the bones.
The oldest skeleton, of a man aged about 50-years-old, is thought to date back to the reign of King Canute (1016-1035) and has been restored to its original oak coffin.