Gardaí have recovered the head of an 800-year-old 'Crusader' that was stolen from the crypt in St Michan's Church in Dublin.
Another skull was also recovered in the operation by gardaí based at the Bridewell Garda Station in Dublin.
The crypt was also badly damaged and several of the mummies, including the 400-year-old remains of a nun, were desecrated in the incident.
The items were recovered after "information came into the possession of the investigating gardaí".
Gardaí said the National Museum of Ireland was acting in an advisory capacity.
They thanked the public for their help and said the investigation was continuing.
Archdeacon David Pierpoint had described last month's incident as "a sad day for the church and a sad day for humanity".
Gardaí have recovered the head of "The Crusader" and another skull taken from a crypt in St. Michan’s church over the weekend of 23rd/25th February. We would like to thank the public for their help. The investigation in ongoing pic.twitter.com/CdfOJUQmQV— Garda Info (@gardainfo) March 5, 2019
The United Dioceses of Dublin and Glendalough has said it was "delighted" that the items have been recovered and thanked those who secured their safe return.
In a statement, Church of Ireland Archbishop of Dublin Dr Michael Jackson described the items as "a priceless part of the heritage of the city of Dublin and its citizens".
He added that "the emphasis will now be able to turn to consideration of future security and display of the remains in the crypt of St Michan's".