A few weeks ago I wrote about the 'mystery stone' in a field near Kilchoman between the old and ruined Kilchoman church and the graveyard for the soldiers from the Tuscania and Otranto, who died in 1918 during a terrible tragedy. Someone pointed out that it was a sanctuary stone but I still had some other questions regarding this stone and possible other sanctuary stones. Questions like where are the other three stones? Who put these stones there and when? In the meanwhile I dug up some more information and contacted Malcolm Ogilvie from the Islay Museum for information.
First of all, what is a sanctuary or an area of sanctuary? A sanctuary is an area around a church marked by 4 sanctuary stones or cross slabs on each corner. A sanctuary stone in the kirkyard marks the centre of an 'area of sanctuary' that once extended one Scots Mile around (A Scottish mile was the same length as the Royal Mile in Edinburgh, i.e. from the castle down to the Holyrood Abbey which is 1.8km.) These sanctuaries date back to medieval times. In a sanctuary in medieval law the Church acted as a place of refuge. Sanctuary was also a right to be safe from arrest in the sanctuary of a church or temple, recognised by English law from the fourth to the seventeenth century.
A sanctuary as a sacred place. In Europe, Christian churches were usually built on a holy spot, generally where a miracle or martyrdom had taken place or where a holy person was buried. Examples are St. Peter's Basilica in Rome and St. Albans Cathedral in England, which commemorate the martyrdom of Saint Peter and Saint Alban, respectively. The place, and therefore the church built there, was considered to have been sanctified (made holy) by what happened there.
Back to the sanctuary stone at Kilchoman, what follows is Malcolm Ogilvie's answer for which I'm very grateful. Malcolm: Certainly two sanctuary stones have been identified near the Kilchoman Church. The still standing one out in the field towards the sea is, according to the Inventory of Monuments in Argyll (vol. 5), 330m SW of the Church and marked on the Ordnance Survey maps. The second stone, according to the Inventory, lay beside a track on a hillside 380m ESE of the church and this is the one which is at the Museum.
The Inventory says that the presence of the two cross-slabs 'suggests an Early Christian church of some importance' and goes on to make comments about a Medieval parish church with dependent chapels elsewhere on the Rhinns, so one has to assume the stones date from the same period.
There is no suggestion in the book whether there should have been more, but I know that some early Christian churches marked their sanctuary areas with four stones. I've not heard of a case where the church would have been a sanctuary marker itself, because the sanctuary would be all round the church, with the stones at about the same distances from it and at four equi-distant points of the compass. At Kilchoman, the most likely arrangement would be two more cross-slabs at, roughly, 350 m to the NE and NW. One can imagine one to the NW being overwhelmed by sand, while the one to the NE could have been moved by a farmer, or even incorporated into a stone wall.