Preserving Numismatic Context from Destruction by Archaeologists
Serious issues have arisen between collectors of ancient coins and archaeologists, regarding their competing claims to possess these relics of ancient economic history. Archaeologists value coins as a dating tool, and also fear that detectorists looking for coins will disturb archaeological sites seeking buried coins. Collectors view this as unlikely, since as Grierson  noted, almost invariably location and excavation finds share two characteristics making them nearly worthless commercially: low denominations and very poor condition.
Perhaps because of this questionable concern about protecting sites from detectorists, a great deal has been said about the extreme importance of archaeological context and the necessity of protecting it from assaults by “looters,” a term often used by archaeologists to describe those who go out prospecting with metal detectors.
Archaeological context is, briefly, the sum of the physical and spatial relationships linking buried objects with the neighborhood of their interment, other objects in the area and nearby structures, and local trade, industry and habitation history. Each buried object has its own context, and each interrelated group of objects shares a higher context that is of importance in assessing and interpreting the archaeology of a site.
The archaeology of a site is in itself a still greater context, and thus we by degrees eventually arrive at an archaeological world-view in which every site and ultimately every object is interlinked in a web of context from which nothing may be removed (except by an archaeologist) without to some extent irreversibly disturbing and diminishing the entirety of Context, the capitalized form denoting the sum of all local and individual contexts. Thus one cannot think of context as something that is bound to or possessed by an individual object – it is a shared property.
In responding to a recent critical comment by an archaeologist , I remarked that numismatic methodology has made it possible to establish accurate event sequences and chronologies covering many poorly documented areas of the historical record. In doing so, numismatics has contributed a large part of what humanity knows about the history of a number of important civilizations, such as the Parthian Kingdom, as well as smaller but still very significant areas of our knowledge of other civilizations, including parts of ancient Greek and Roman history. That is certainly a contribution of immeasurable value to human culture, a contribution which has extended over a period of more than five centuries – beginning long before anyone ever thought of the word “archaeology.”
Context is also of capital importance in the numismatic method. Numismatic context, however, is not by any means the same thing as archaeological context. It is instead mostly concerned with the systematic study of dies and die-links, and also with the study of coin hoards and their dating. In studying coin hoards, numismatists are only interested in the location and contents of a hoard, and the accuracy to which it can be dated by non-numismatic evidence. Other aspects of archaeological context make very little or no contribution to numismatic knowledge.
It would really be more precise to say that numismatics is the study of dies, their lives and their families. Every ancient coin was struck from a hand engraved die that was unique and individually identifiable, quite unlike today’s mass produced identical dies. There are few extant examples of ancient coin dies, and nearly all are now attributed as being the work of counterfeiters. Thus, the numismatist is left with no means to study ancient dies other than working from their impressions (coins), in a manner analogous to a palaeontologist studying dinosaurs from their footprints. Coins usually being relatively well preserved, much has been learned about the surfaces of the dies that formed the coins, although knowledge of other aspects of the minting process is generally very incomplete.
The processes by which dies wear, recutting to extend their lives and also evolution of stylistic trends and engraving "hands," provide insights permitting die aging and succession sequences to be built up in a manner very similar to tree ring sequences compiled by dendrochronologists. These detailed linear die sequences can then be crosslinked to other linear die sequences through analysis of obverse/reverse die pairings, evolution of die preparation technique, etc. to create matrices of die evolution.
These die evolution matrices can correspondingly be related back into the historical record primarily through study of epigraphic and typological evidence, i.e. careful concordance of honors, titles etc. included in coin legends, secondarily through visual aspects of coin devices, such as apparent age of the ruler, the manner of portrayal, headdress, etc. The result can be dates accurate to within one year. This typological die-evolution methodology was fully worked out by the late Robert Göbl . It is applied throughout his many landmark studies, the most accessible today being "Sasanian Numismatics," still the standard one-volume reference.
In theory this method should yield a complete net identifying, describing and placing every ancient die. Unfortunately the numismatic record, like the fossil record but unlike the archaeological record, is sparse. There is at least something left from most major inhabited places, but numismatists know all too well how few coins have survived from the enormous numbers originally issued – optimistic estimates are on the order of one in 10,000. Since that is not much more than the number of coins struck per die, it is clearly a matter of chance whether any individual die becomes included in the overall context of die matrices, and the odds of that are not too good. There are great gaps in our knowledge of ancient numismatics resulting from the large proportion of dies missing from the numismatic record, certainly far more than those that have been recorded.
This is demonstrated in numismatic practice by the frequency with which previously unknown coin types are continually being discovered. I have myself identified two coins previously unknown to science during the past four years, and many other professional numismatists have found even larger numbers of unpublished coins. That parallels the experience in palaeontology, where the supply of new species to be discovered is seemingly inexhaustible – whereas the supply of new cities and civilizations to be discovered by archaeologists is not.
Because the active discovery of new coin types is continually adding to the known numismatic context, increasing the precision of our knowledge of dates and issue sequences, and even occasionally identifying a new ruler previously unknown to history, numismatics is today – more than ever before – a vital, living science. That is true only because there is a large and steady influx of “new coins” coming into the numismatic trade, where some sharp-eyed dealer or collector will spot anything unusual about a coin type that has not previously been published.
Numismatic methodology has proven to be a precise, powerful, and comprehensive tool important to human knowledge and culture, for reasons extending far beyond the interests of coin collectors. Thus, it is clearly essential to assure that the pace of coin discoveries does not decline and that all newly discovered coins are made available to numismatic researchers, so that their contribution to numismatic context can be properly assessed, recorded and published. This is certainly at least as important to the interests of humanity as recording the debatable archaeological context of coin finds, which in more than 90% of recorded examples are discovered in out of the way places without other context.
In our imperfect world, one often faces a choice between two unsatisfactory and disagreeable alternatives. Since the obstinate refusal of archaeologists and cultural ministry authorities to cooperate with collecting and the numismatic trade has prevented organizing a sensible, cooperative and regulated approach to disposal of new coin discoveries, these new coins presently flow into the numismatic market through a variety of clandestine channels, where they intermix with vast numbers of unprovenanced coins coming onto the market from scores of thousands of existing collections. At least one can say for this uncontrolled, admittedly imperfect process, that there are very good odds that any new coin type will come to the attention of science.
Surely that process is a lesser evil than that a coin should be licitly excavated, then cursorily examined without any interest other than its stratigraphic dating potential, and consigned to molder away in unconserved storage where no numismatic scholar will ever learn of its existence.
 Grierson, Philip: Numismatics (137). Oxford, 1975, 211 pp.
 Göbl,Robert. Numismatik. Grundriss und wissenschaftliches System. München, 1987. 315 pp.