A sepulchral stone from a domestic or portable altar, unearthed during a “dig” in Sigtuna. The stone is Greek porphyrite, ground and polished, and in all certainty once fitted into a wooden altar.
The stone measures only 6 x 6 cm, but the absence of any surviving edges suggests that it used to be bigger. Its green surface, ground and polished, heightens the outstanding quality of the material.
The sepulchral stone was fitted into a domestic or portable altar – a simple, movable altar of wood, not intended to be permanently stationed in a church. In the north of Europe, altars like this are especially common from the missionary period and the years of Christianisation. Very few such portable altars have survived intact. The stone served as a closed lid marking the position of a reliquary. Every altar had to have at least two relics enclosed in it, and during the celebration of the mass these served as a link with those who had gone before in the faith.
The altar consisted mainly of wood, and the polished surface of the sepulchral stone marked the altar and the special significance of the relics. When the altar was used for celebrating mass, a miniature church was created round about it. The reliquary inside the movable altar then replaced the graves of saints which had to be present in all consecrated churches. All altars, portable and domestic ones included, had to be consecrated by a bishop, which further underlines their specific function and the fact of their forming a church interior when in use.
This kind of altar was very common in the Eastern Church, which further underscores the close contacts existing between primitive Christianity in that Church and in Sigtuna. Sigtuna is the foremost find location in northern Europe where sepulchral stones are concerned. This one probably dates from the 11th century and belongs to the period when Christianity first took root in the town.