The bowl on this photo, which you can see in the National Archaeological Museum in Athens, is an ‘incantation bowl’. It is decorated with an almost endless, spiraling text that is supposed to protect the owner against a host of evil spirits. These bowls were made in Sassanian Mesopotamia and were used by every religious minority. There are Christian incantation bowls, but they were also used by Jews, Manichaeans, Zoroastrians, and Mandaeans. I remember from my visit to the the museum that this particular bowl was Mandaean, but I cannot check it.
After all, what do I know about Mandaeans? Hardly anything is known about them. We know a bit of their theology: they are dualists who believe that the soul wants to be with God but is in exile on earth after a Great Cosmic Accident. However, there is secret knowledge that helps the soul return to its origin and destiny. This theology is not unlike the Gnosis of Antiquity and it is probably no coincidence that the name of this faith is derived from Aramaic manda, which means “knowledge”, just like Greek gnosis.