Researchers think this stone slab

was once the decorated front of a medieval high altar

of Jerusalem's Church of the Holy Sepulchre

The church is the site of Jesus's crucifixion and burial

(SOUNDBITE) (English) AMIT RE'EM, JERUSALEM REGIONAL ARCHAEOLOGIST FOR ISRAEL ANTIQUITIES AUTHORITY, SAYING: "Why the stone was forgotten? Because it was situated in one of the dark corners of the Holy Sepulchre, lying upside down on this flat surface. Nobody knew what is the purpose of this stone, who brought it from here and by whom it was situated here. But everybody knew that this stone is the graffiti stone of the Holy Sepulchre and write their names on the smooth surface of this slab. When the slab was turned during the recent renovations, amazingly, we found this piece of marvelous art.''

''You cannot see it now, but originally it was inlaid with pieces of precious marble, pieces of glass, pieces of small, finely made marble. It was shining and this was a really amazing artefact."

Researchers identified the unique decoration method as 'Cosmatesque'

which combines Classical, Byzantine and early Islamic art

featuring finely cut pieces of colorful marble

Similarly decorated altars have been found inside churches in Rome

dating to the 12th and 13th centuries