Ceramic mould in two halves, both still retaining the impression of the actual lamp which would have been made in terra sigillata and possibly manufactured in Northern Africa, where similar examples have been unearthed.
This oil lamp would have lit homes during the early flourishing of Christianity. The centre of the lamp is decorated with the Labarum, an overlapping X and P representing the Greek initials of Jesus Christ. This is one of the earliest symbols for Christ and is found in Catacombs, early signet rings, and ordinary objects such as this lamp. Interestingly enough, the design impressed on this very mould is very much alike the one stamped on one of our terra sigillata lamp (LO753), suggesting that they both could have come from the same centre of manufacture in Northern Africa and after many centuries of separation, reunited for our marvel.
For a comparable example see: D. Buckton, Byzantium, 1994: no.47, p.60. - (LO.721)

Antique Lamps and Lighting
Antique Oil Lamps