Mandaean texts are transmitted in manuscripts copied by priestly scribes, and the copies carry colophons that record the chain of copyists standing behind them. A colophon is not a decoration; it is a statement of who copied this book from whose copy, and back through the line.
That habit has an unusual consequence. It leaves a documentary record of transmission running back a very long way, and modern scholarship has been able to work with those chains as evidence in their own right, which is something few textual traditions of comparable age make possible. The copying is a religious act as well as a technical one, and the record it leaves is a by-product of taking it seriously.
There is a source problem alongside it, and it should be stated plainly. A great deal of what was published about Mandaeism in Europe from the seventeenth century onward came through missionaries, travellers and colonial officials, who named the community by their own categories and had their own reasons for describing it as they did. Where that material is the only evidence for a claim, the claim is only as good as the witness, and this atlas says so rather than repeating it as established.
The community's own texts, copied by its own scribes in these letters, are the primary record. What they mean within the tradition is the priesthood's to say.