A burial stone is a method of blocking burial caves and other narrow openings.[1]
The stone's purpose is to prevent from unwanted visitors and animals enterring the burial system.
In the Land of Israel, square blocking stones are common in burial systems from the First Temple period, adapted as a cork for the opening of the rock-cut tomb system.[2] Even when the blocking stone is not present in the area, it is visible that the burial cave was sealed with a stone by the chippings of the edge of the cave opening. Burial caves of this type can be seen on the slopes of Kfar Shiloh, in front of the City of David.
In Second Temple period burial systems, round blocking stones that move on a rail and seal the opening, can be found.[3] The stone was intentionally large and heavy, it needed a joint effort of several people to move it, making it difficult for grave robbers and vagabonds opening or breaking in. Tombs with such blocking stones can be found in the Hurvat Midras, in a preserved burial cave on the "Jo'ara road" (6954), near its intersection with road 66 and in the Tombs of the Kings in Jerusalem. There are common legends about special mechanisms for rolling the heavy blocking stones, but no evidence of such mechanisms has been found.[4]
Apart from a physical barrier preventing the entry of men and pests, the blocking stone had another purpose that was to prevent ṭumah (impuriity) exiting the cave. The Mishnah, Tractate Oholot, Chapter 15, Mishniyot 8 - 9 teaches that various objects can be used as a blocking stone in order to prevent impurity from leaving, but the main advantage of the stone is that it does not receive ṭumah, (see also Mishna Torah to Rambam, Book of Taharah, Laws of Dead Impurity, Chapter 6).
Evidence of the use of blocking stones for security purposes can be found during the Roman period in the Land of Israel. During the Bar Kokhba revolt, blocking stones were used to seal the rebels' hiding systems.[5]
In many excavation sites in the Land of Israel, especially sites in the mountain area from the Byzantine period, large rolling stones and rails for rolling them were discovered at the entrances of public buildings (such as synagogues). The courtyard of the building was surrounded by a solid wall and had a single and relatively narrow opening. At the opening threshold a rail was installed and on the sides of the opening niches were designed in the wall and in them was placed the blocking stone. This made it possible to safely close the place when not in use and store valuables inside. Only a joint effort could open the building's blocking stone, this prevented a single man enterring the place. It also made it possible to create a safe gathering place for the settlements' population, who could escape to a public house and shut themselves inside fortifying themselves against enemies.