The stele (plural stelae), as it is called in an archaeological context, is one of the oldest forms of funerary art. Originally, a tombstone was the stone lid of a stone coffin, or the coffin itself, and a gravestone was the stone slab that was laid over a grave. Now, all three terms are also used for markers placed at the head of the grave. Some graves in the 18th century also contained footstones to demarcate the foot end of the grave. This sometimes developed into full kerb sets that marked the whole perimeter of the grave. Footstones were rarely annotated with more than the deceased's initials and year of death, and sometimes a memorial mason and plot reference number. Many cemeteries and churchyards have removed those extra stones to ease grass cutting by machine mower. In some UK cemeteries, the principal, and indeed only, marker is placed at the "foot" of the grave.