I am not quite sure what you mean by "it became immobilized" Is it found on a variety of denominations
Could something "start off as an artist's mark and end up something else"?
I am not really familiar with Ptolemaic, I am just a little familiar, and would like to know more.
It is felt that the tiny Δ appears on too many dies for them to be the work
of a single engraver. For it to be an artist's signature that became immobilized, would mean that it was copied by subsequent engravers, possibly not knowing what its original meaning was. This is perhaps less likely because the tiny Δ continues through changing type
, and it is also used on many denominations
as well. The tiny Δ lasted into the coinage of Ptolemy
II, finally disappearing before circa 275 BC.
Quotes from Catharine Lorber
's ‘Coins Of The Ptolemaic Empire’ Part
1, Volume 1:
Pages 36-37, Cryptic Controls.
“In addition to the conventional controls that appear on the reverses of nearly all coins of Ptolemy
I, there are cryptic controls on many obverses, usually a tiny letter Δ…It is present on many but not all obverse
dies of subsequent Alexandrian tetradrachm
issues, and also occurs on some of the products of the auxiliary mints that operated briefly after the weight
reduction of c. 306. The same tiny Δ was concealed behind Ptolemy
’s ear in his
coinage, beginning with the gold staters and continuing on all the precious metal denominations
introduced in the final reform of 294.”