The Cast Bronzes were produced for sixty-five years, and most of the time the aesthetic qualities were carefully controlled. In general, cast coins tend to become thick and dumpy in appearance and this posed a problem. The Kentish tribes wanted their coins to be more anesthetically pleasing. Casting large, thin coins posed many technical problems and so the success the moneyers achieved is a tribute to their metal-working expertise. All the coins were cast in chains using clay moulds with a runner system connecting the cavities. The methods used to manufacture' the moulds changed over time as the workers perfected their techniques.
For most of the series, the images were scribed freehand into the clay moulds. Traditionally, these images have been used to establish a type sequence widely used in archaeological work. Today however, the coins are seen to be mass-produced items. The stylus work was done as quickly as possible and thus the images provide little basis for establishing the sequence.
A better indicator of types are the marks produced by the different mould manufacturing processes. These yield a plausible chronological sequence, consequently, the following catalogue is primarily concerned with the mould manufacturing techniques. The images are taken into account only when major differences in artistic style are noted. For example, at some point the images on the reverse switch from curvilinear forms to boxy ones. The change may indicate the appearance of a new moneyer or a modification to the coining techniques.
The first three periods of manufacture occurred quickly and in rapid succession, as the moneyers sought the best production methods. After the techniques were perfected, an enormous number of coins were produced over a long period. Quantities of hundreds of thousands (perhaps millions) are thought to have been cast and several thousand examples exist today.
The moneyers worked to eliminate the problems during the Innovative Period. Various techniques of producing the cavity-and-runner system were tried and experiments to create smooth mating-surfaces were carried out—all producing striations in the coins' fields. Four types of striations have been identified: CROSSED, MEDIUM, HEAVY and THIN, each revealing a different technique of mould production.
The Crossed Striations were produced by textile pressed into the clay to form the cavity and runner system. Medium Striations were the result of cutting a block of clay in two with a wire in an attempt to produce perfectly-mating moulds. Heavy Striations were produced by pressing the clay against a wooden surface to smooth it. None of these techniques was particularly successful— either excessive flash resulted or the striations were so severe the stylus image was ruined.
The Thin Striation coins are the commonest, because the technique was more successful and was employed for a longer time. These were produced by smoothing the clay with a flat scraper.
The transition to the Optimization Period is marked by an extremely rare type with three pellets in the Apollo head. A Thin Striation predecessor with the same pellets may exist. The first coins continue with a bull made up of curved lines, however at some point a change was made. The bull was given a boxy appearance by using straight lines in place of the curved ones.
A suspected transitional issue is known, with a bull having both straight and curved lines. This unusual issue is denoted by a pair of crescents under the exergual line. It is an extremely rare type and the only one displaying crescents. The date of manufacture is difficult to determine—it probably occurred early in the Optimization Period.
Alternatively, a time of overlap in which both curvilinear and boxy bull images were produced is also possible. Recently, the Stansted Airport Hoard appears to have yielded a striated coin with the boxy image, but this has not been confirmed. The relative chronology of the Innovative and Optimization Periods, at the moment quite problematic, may become clearer as more coins are discovered.
The vast majority of the coins in existence today were produced during the Optimization Period using a new mould-making method. The procedure was extremely successful and yielded exquisitely thin and flat coins—probably the most expertly-produced cast coins known. The clay moulds were pressed against a very smooth material, probably sheet bronze. This yielded moulds that had no striations to ruin the image, yet mated well enough to produce minimal flash. The only remaining problems were either one, the coins were so thin they cracked upon separation from the chain, or two, the moulds were so thin they failed to fill during casting.
These last two problems, incomplete casting and unsuccessful separation, were solved by a change in policy just before the introduction of the Struck Bronze series. The final cast coins were made small and thick—although they were dumpy and unappealing, they could be produced with no separation or mould filling problems.
Generally, the various types of cast bronzes are extremely rare. However, the optimization period issues were made in vast quantities over a long time and are today very common.
Caesar named four Celtic rulers in Kent, implying several tribcs inhabited the area. The Kentish tribes, he declared, were amongst the most advanced in all Britain. His testimony is supported by the coin evidence the Kentish coinages are amongst the most sophisticated of all those in Britain.
Beginning about 125 B.C., the tribes along the Kentish coast received the first imports of continental coins. Within fifty years, a money economy existed to the extent that small-value coins were needed to facilitate trade. The first coins produced in Britain, starting about 100 B.C., were the Kentish CAST BRONZES. These reveal a remarkable knowledge of casting techniques and show how the Celts applied their innovative spirit to practical manufacturing problems.
Imports of gold staters and quarters allowed the Kentish tribes to forestall striking their own gold coins, and it was not until after the Gallic War they produced their first die-struck coins. When production began, however, a number of types were produced simultaneously, suggesting more than one tribe inhabited the region.
Around 30 B.C., Dubnovellaunus-in-Kent struck the first inscribed staters, these were later replaced by coins inscribed Vosenos. Sometime after 10 B.C. Vosenos disappears and Atrebatic/Regnan types appear with the name Eppillus. An Atrebatic/Regnan incursion appears likely, lured by the absence of a strong Trinovantian/Catuvellaunian leader to prevent it. Previously, small numbers of Trinovantian/Catuvelluanian coins appeared in Kent, suggesting Tasciovanus had been extending his economic influence over the area.
Sometime after 10 A.D.. Eppillus was driven from Kent and the region came under the direct influence of the Trinovantes/Catuvellauni. At this time, local coinage was suppressed by Cunobeline and Trinovantian/Catuvellaunian coins became the only circulating medium in Cantian territory. Shortly before the Claudian invasion, a Kentish coinage reappears in the name of Amminius. a leader who evidently seized control after the death of Cunobeline. This final coinage was short-lived, ending when the Romans invaded in 43 A.D.