The second Abbasid caliphate or epoch is well defined numismatically. It begins with a general coinage reform by the caliph al-Ma'mun, completed by his successor al-Mu`tasim with one final touch early in his reign in 834; and it ends with the Buyid takeover of power in Baghdad in 946. During this period the Abbasid caliphate had a general uniform coinage system that underwent no major change, despite all the vicissitudes the caliphs themselves suffered. In most respects, the system continued well into the Buyid period and after. This was the era when the classical Islamic coinage system was established.

Al-Ma'mun's reform is not mentioned by any medieval writer. We know it only from the coins. It is the subject of an important article by Tayyib el-Hibri in JESHO 1993.(1) For convenience, the reform can be dated to the year 206 or 821-22, in which year the final version of the new-style coinage was first issued in Baghdad, but there were several elements of the reform that were introduced at different times, and the reform was not begun at some mints until it was finished at Baghdad. A number of mints simply were closed. I will not attempt to describe the reform and its progress in detail here, but a useful way to describe the system of the post-reform era is to contrast it with the system before al-Ma'mun's changes.

The central element of the reformed system was the absolute uniformity of the coinage at any given time. The pre-reform system was extremely diverse: although the main inscriptions were substantially the same, most coins had subsidiary inscriptions that varied from mint to mint at any one time, and were changed often. The inscriptions on gold dinars and silver dirhams differed and were arranged differently. In contrast, once al-Ma'mun's system was introduced, all gold and silver coins, throughout the caliphate, had the same inscriptions arranged in the same way. Dinars and dirhams had the same two obverse marginal inscriptions surrounding the shahada in the center, and they had on the reverse the same marginal inscription surrounding the words lillah and Muhammad rasul Allah. All precious-metal coins for general circulation, throughout our period, had these inscriptions in these locations, as did nearly all such coins until the fall of the Abbasid caliphate. Even the epigraphical style and general design of the coins was absolutely uniform, from Egypt to Samarqand.

One major element of the diversity of the first Abbasid era, before al-Ma'mun's reform, was the plethora of officials that were named on the coins, ranging from the caliphs down to unidentified local officials. Hundreds of people are named on coins in the period from 750 until 833. Nomenclature even for one individual was diverse. The caliphs themselves were designated differently on the contemporary issues of different mints, with no discernable pattern. The caliph al-Rashid, for example, is called al-Khalifa Harun, al-Khalifa al-Rashid, Harun Amir al-Mu'minin, and even al-Khalifa al-Mardi. More often than not, however, the caliphs were not named at all on the coins.

In its earliest phase, during al-Ma'mun's reign, the reform swept all this nomenclature away, completely: the coinage from the reform until al-Ma'mun's death was anonymous, returning in this respect to the original practice of the Umayyads and early Abbasids. Fortunately for numismatics and history, this severe anonymity did not last. Al-Ma'mun's brother and successor al-Mu`tasim put his own name on the coinage, in the position of third rank after God and the Prophet, below the reference to Muhammad the reverse field. Al-Mu`tasim did this, not at the moment he became caliph or as soon as convenient, but rather, judging from the evidence, on the first day of the first year that began after his accession. That is, all the coins of the year 218 (833-34) in which he became caliph are anonymous, while all the coins of the next year, 219, have his name on them.

Although al-Ma'mun's program was in this respect modified, the principle of uniformity was maintained. Al-Mu`tasim and his successors use only one form of their name, their honorific regnal title, always in full and with (save two exceptions) no titles of office. In passing, although it is not a strictly numismatic phenomenon, we may note another titular innovation by al-Mu`tasim. He is the first caliph to have a billah to his name. His name in that full form, al-Mu`tasim billah, appears in the same position on all coins of his reign and his successors were all named in the same form in the same place on all their coins throughout the caliphate, even on coins with the names of provincial governors such as the Tulunids and Samanids, whose coinage also conformed in other respects to the rules of the central administration. It is not realistic to regard the coins issued under these various provincial dynasts as separate coinages for separate governments. The coinage issued in mints under their control was Abbasid coinage, part of the Abbasid monetary system, and circulated throughout the caliphate along with coins issued in other places with the caliph's name only.

The two caliphs who modified the standard nomenclature slightly were both legitimacy-challenged: al-Mu`tazz, who added the title Amir al-Mu'minin to his regnal title, perhaps as an assertion of his prior claim against al-Musta`in; and al-Mustakfi, who was put on the caliphal throne by a particularly distasteful warlord after the treacherous deposition and blinding of his predecessor. Al-Mustakfi at first added the title khalifa to his regnal title, and then replaced that with Imam al-Haqq, the Imam of Truth.

The only significant change in the coinage of the caliphate during the century of this discussion was in fact in nomenclature. These changes were bound up with evolution in Islamic onomastic in general. The reform began, as I said, with anonymity: no one was named on the coins. Then al-Mu`tasim put his regnal title on coins, in which respect he was followed by every subsequent caliph. The next step came when al-Mutawakkil added the name of his son and intended successor Abu `Abd Allah to the coinage precisely at the beginning of the year 236 (850). This name was put in the position of second rank for a living person, below the inscriptions in the center of the obverse. A little over four years later, when Abu `Abd Allah with his two brothers received the oath of the Muslim community as wali al-`ahds, they all received titles and Abu `Abd Allah's title al-Mu`tazz billah replaced his kunya on the obverse of all coins of the caliphate.

Most subsequent caliphs, if they lived long enough, also put the name of a successor on the obverse in the same position. The coins of this period are in fact quite informative about the selection of successors by the caliphs. Eleven different Abbasids are named on coins as successor. Practice in this respect differed substantially from practice up to al-Ma'mun's time, both in the designation of successors and their nomenclature on coins.

Before the reform, except for very brief caliphates, every Umayyad and Abbasid caliph from Mu`awiya to al-Ma'mun chose one or two or more successors, who received the oath of the Muslim community as the next caliph or caliphs in succession. Al-Ma'mun had two wali al-`ahds, one which he inherited and then deposed, and another that he chose, the Alid `Ali al-Rida, who subsequently died. After that, al-Ma'mun departed from the practice of his predecessors: he did not have the oath sworn to any successor. He was the first caliph since `Ali to die without leaving a designated successor who had received the oath of allegiance in advance. His successors al-Mu`tasim and al-Wathiq followed his practice.

In fact, as the coins show and the histories confirm, the creation of a wali al-`ahd, that is the swearing of oaths of allegiance in advance to a successor, became the exception rather than the rule after al-Ma'mun. In the period of our interest, of the seventeen caliphs, six never designated any kind of successor. These included some who reigned briefly and did not have time, but they also included four of the most powerful and effective caliphs, al-Mu`tasim, al-Wathiq, al-Mu`tadid, and al-Muktafi. Of the remaining eleven, only two had oaths sworn to create wali al-`ahds, but these two, al-Mutawakkil and al-Mu`tamid, had three apiece. The wazir in both cases was `Ubayd Allah b. Yahya b. Khaqan. I regard these two exceptions as deliberate attempts by him to revive older practice.

The remaining caliphs designated successors who would not be known as such but for the coins. Some of them are not not even named in the literature, but in the majority of cases there are obscure references in the histories, belletristic literature or poetry to some distinction of the son named on the coins. These references have not been understood to identify the son as the designated successor. And yet, if a son is named on all coins to the exclusion of all other sons, how can he not be his father's intended successor? In addition, the fact that these are intended successors, but not wali al-`ahd, is confirmed by poetry by figures like al-Buhturi who congratulate the caliph and the successor he has designated, and urge him to promote the boy to wali al-`ahd-dom. These successors, many of whom were quite young, in one case a newborn, served insofar as they were able as their father's representative on official occasions, were often appointed honorary governor of the Hijaz, apparently received the right to be addressed as amir, and never once, as it happened, actually succeeded when their father died. For that matter, only one of the six sworn wali al-`ahds actually became caliph in succession. Some in both classes made it to the caliphate later; others disappear from history.

On the coins, the intended designated unsworn successors are named with their name or ism alone, or most often by their ism or kunya combined with the appellation b. Amir al-Mu'minin, while successors who had received the oath are designated by the honorary title they were given. Three successors are named first with their ism and then named by their title, when they received the oath. Otherwise the designation of each heir is always the same and always conforms to the rules. This consistency contrasts with the pre-reform period when the successors, like the caliphs themselves, were designated in various ways on coins. A more important contrast is that, in the pre-reform period, the successors like the caliphs were not named on coins everywhere. I agree with Bacharach's suggestion in his recent article on al-Amin's successors(2) that the successors were named on Abbasid coins of the first period not because they were successors, but for the same reason that anyone else was named on coins: because they had administrative authority over the territories and mints where they were named. In contrast, in the second period, the wali al-`ahds and the designated successors are named everywhere, uniformly, throughout the caliphate. They are named because of their personal status, not because of their administrative position.

During this period other officials began to be named on coins. Three wazirs are named, at intervals of a generation. This was an innovation with no permanent effect: scarcely any wazirs are named on later Islamic coins. All three wazirs had extraordinary positions combining military authority with their normal civil power; the three who are named are also the only three wazirs to receive a personal title of honor in this period. In many respects these three presage the amirs al-umara', who also combined civil and military authority.

There were six amirs al-umara' from 324 to 334 (936-46), of whom only four were named on coins. As with the wazirs, the amirs al-umara' who were named on coins were the only ones who were granted an personal title of honor. To complete the list of those named generally on the coinage controlled by the central authorities in the second caliphate (there were only 33 individuals during the span of 116 lunar years), there were two brothers of amirs al-umara', Sayf al-Dawla the Hamdanid and `Imad al-Dawla the Buyid. These again were the only men in their category to have honorific titles. In sum, being named on the centrally-controlled coinage in this period was still a rare honor granted by the caliph to a very few men, as part of a package that also included other honors such as a personal title, the right to be named by one's kunya in the caliph's presence, and so on. No one at the center simply decided independently to name himself on the coins, nor did anyone for a generation or so under the Buyids. The right of the caliphs to be universally named on coins, and their monopoly of the right to allow others to be named, were the basis of the Islamic concept that being named on coins was an indication of sovereignty. The development of the concept was reinforced, of course, by the fact that only the most powerful warlords could dare to infringe the caliph's rights.

These statements are qualified to refer to the central coinage only, because there are quite a few others named on provincial coins as governors, despite al-Ma'mun's abolition of the practice. Aside from the Aghlabids of North Africa, who had done as they pleased since the time of the civil war between al-Amin and al-Ma'mun, the first governor to be named on Abbasid coins of the second period was probably Ahmad b. Tulun of Egypt in 265 (878-79). Other well-known instances include the Samanids and the Saffarid Ya`qub b. al-Layth, but there are a fair number of others, not all of whom are regarded as independent. There have been separate studies of various dynasties who established their power sufficiently firmly to be regarded as independent, but there is no general comparative study of the phenomenon. Who in fact was the first governor? (That is, after al-Ma'mun's reform.) How many different individuals were named on provincial coins of the caliphate (in addition to those who were named universally)? Most importantly to my mind, how did it happen that a governor began to be named on coins? Did he simply do it, or was the right granted to him by the caliph? What was it that qualified, or enabled, some governors to name themselves, but not others? Various responses spring to mind, but the truth is that we know nothing about it. I have not found a single notice, in the histories or in any early text, of a governor beginning to be named on coins, let alone any explanation for it.

In these few minutes I have to leave aside several aspects of the coinage system. I can't say anything about the monetary function of the coins, except that the alloy of gold and silver coins, so far as we know, was as high as possible. I believe, without much in the way of proof, that it was about this time, perhaps as a feature of al-Ma'mun's reform, that the 10:7 weight ratio between dinar and dirham was established and as a result became canonical in the Shari`a. Ironically, it was also during this period, according to unpublished work by Lutz Ilisch, that fixed weight standards for coins were abolished. Henceforth in the Islamic world the value of coin payments was measured by weighing a mass of coins, not counting them.

I also cannot say anything about the copper coinage, except to note that in fact copper coinage seems nearly to disappear during the early years of this second Abbasid period, and does not reappear for centuries. It was perhaps as a result that hoards of silver coins in this period, unlike earlier ones, often include small coin pieces, that were cut either for payments smaller than a dirham or to bring up the weight of a mass of coins to a round number.

There is one feature of the system, a somewhat surprising one to me, that I would like to devote a few words to in conclusion. Toward the end of this period, in the reigns of al-Muktafi and al-Muqtadir, we find a number of coins that are struck from dies that have been re-engraved to replace one mint city name by another. That is to say, an obverse die that was already fully engraved with inscriptions, including the name of a city as the mint place for the coins to be stamped with the die, had another city name engraved over the original one, re-utilizing as many as possible of the strokes that formed the letters of the first name. Such coins are not common in proportion to the total of known examples, but they are not entirely infrequent. The first article on the subject, by Lutz Ilisch in 1979, listed 20 such coins from 13 city pairs.(3) Quite a few more have since been reported. The one you have been looking at is a dirham minted in Nisibin from a die that was originally made in Isbahan. Here is another from al-Rafiqa recut from a die for Shiraz. They are all in the belt from al-Jazira through to western Iran, the only territories the caliphs still administered.

The only reasonable explanation of the phenomenon is that the dies used by all mints to stamp the inscriptions on coins were made at a central location, presumably Baghdad, and sent out to the mints. The dies that were used for these coins were originally engraved with the name of one city to be sent there for use, but for some reason the name of the first city was cancelled by engraving a second name on top of it so that the die could be used there instead.

This phenomenon as I mentioned is seen for the most part only toward the end of the second period of the caliphate. I would suggest, however, that the visible evidence that forces us to believe in central die engraving is not a normal feature of the system; it is a product of its breakdown. A well-ordered system would not resort to such makeshifts. New dies would have been made from scratch. When the system worked right, it would destroy its mistakes and start over.

I would suggest therefore that centralized die engraving was introduced long before we see the first errors. It seems entirely possible that centralization of die engraving was part of al-Ma'mun's general reform of the system of monetary production. Uniformity of coin inscriptions and design throughout the caliphate was enforced by producing the dies for coins at a well-supervised central location. This hypothesis can probably be proved or disproved by careful examination of the coins, to see, for example, if the same engraver's distinctive way of using his tools can be detected on coins from different mints. In the meantime, the hypothesis helps explain some otherwise puzzling phenomena, connected with the frequent introduction of numismatic changes at the beginning of the next calendar year and not immediately at the time of the corresponding event. The total process, including the manufacture of a large number of dies with the different mint names and their shipment under guard to the right places, must have been expensive and time-consuming. It had nevertheless to be done at least once every year, since new obverse dies had to be made with each year's date and new reverses were probably made and sent out at the same time. It is therefore likely that changes in the coins, such as al-Mu`tasim's addition of his own name to the inscriptions, or al-Mutawakkil's public announcement of his son Abu `Abd Allah's selection as intended successor, to mention only two of several examples, were often postponed until new dies were normally made and sent out.

If dies were produced centrally for shipment to places as far away as Fustat and Samarqand, it seems possible that some other aspects of mint operations were also controlled directly from the center instead of through governors; and if a widespread network of mints could be controlled or closely coordinated from the center, we must wonder what other aspects of provincial administration were also run from the center. These are only some of the interesting questions that are raised by the coinage of the second Abbasid caliphate.

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(1) Tayeb El-Hibri, "Coinage Reform Under the `Abbasid Caliph al-Ma'muun,"
Journal of the Economic and Social History of the Orient 36 (1993), 58-83.
(2) Jere L. Bacharach, "Al-Amin's Designated Successor: The Limitations of Numismatic Evidence," Journal of the American Oriental Society 116 (1996), 108-13.
(3) Lutz Ilisch, "Stempelveranderungen an islamischen Munzen des Mittelalters als Quell zur Munzstattenorganisation," in Actes du 9eme Congres International de Numismatique (Berne, Septembre 1979, II: Numismatique du Moyen Age et des Temps Modernes, ed. Tony Hackens and Raymond Weiller (Louvain-la-Neuve and Luxembourg, 1982), pp. 777-83.