Reliquaries, or lipsanothecas, were receptacles with a lid that were used to hold small relics. During the Romanesque and pre-Romanesque periods, as with this piece, they were placed inside altars as churches were being consecrated.
This one comes from Santa Maria de Lillet and is exceptional because of its cylindrical shape and because it is one of the few crafted of alabaster. The piece is decorated with reliefs of geometric borders and bears a text inscribed with Caroline letters.