Karl Morrison starts his chapter on Metrology by saying "Like coin finds and the interpretation of types, numismatic metrology leaves the question of attribution unresolved." (MG 32) In spite of this warning, I think it is possible to make some headway in clarifying attribution to a number of coins represented on this site, specifically those classified as being either Charles the Bald/Charles the Simple. Most of these dual, or ambiguous attributions, are based on Roberts' notes.

In his chapter, Morrison does not attempt to separate CB/CS coins where there is question of attribution. He presents one major frequency distribution for GDR types, which blends rulers. He does present a distribution by size for GDR coins of CS. The sample is fairly small (49) and the distribution wide. Only three of Charles III's coins weigh 1.76 gr (6% of the total) and none are larger than this. This leads me to believe, with a reasonably high probability and degree of confidence, that the coins on this site from LeMans (1.75 gr.) and Quentovic (1.82 gr.) are actually CB rather than CS.

I think it is also possible to tie several of these coins to CS. Morrison reports that 10 of 49 (20%) of CS's coins weigh 1.26 grams or less. Of the combined GDR coins, only 80 of  975 (8.2%) weigh less than 1.31 grams. Clearly there are more GDR coins around than those of just CS that fit the low weight category, but in the total sample his are more heavily weighted toward the lighter coins. Hence, with somewhat less confidence but still a reasonable degree of probability, I think the coins from Rennes and Troyes are associated with CS. The production quality of the coin from Troyes (inferior) argues for later minting. Supporting this conclusion is the fact that none of the clearly contemporary CB coins represented on this site weigh less than 1.43 grams.

The next most likely candidate for attribution is Reims (1.40 grams) as a coin of CS, but this begins to move more clearly into the questionable realm Morrison warns about.

This attribution effort does not imply that Roberts and others who identify dual potential for these mints are incorrect, it means that these specific coins might be attributable. Other coins are really indeterminate based on weight, in that their ranges are similar across rulers.

There are two paired coins that make for interesting comparisions and potential help with attribution. The first set is from Orleans and at the bottom of the page is a second set from Troyes.

AR denier, 21mm, 1.7gr. Obv: GRATIA D-I REX, central KRLS monogram. Rev: + AVRELIANIS CIVITAS, central cross. R1421; MG 948 (which indicates this type is CB/CS); Dep 11A1, 727 (484 examples); Prou 516.

(for a larger version of this coin, click here)

AR denier, 20mm, 1.58gr. Obv: +CRATIA D-I REX, central KRLS monogram. Rev: +AVRELIANIS CIVITAS, central KRLS monogram. Orleans mint. R1421; MG 947; Dep 11 A1, 727 (478 examples); Bel 142; Nouchy CB167. MEC 881/2 which matches to MG948.

There are several noticeable differences between these two Orleans coins. The first is heavier (1.7gr. v. 1.58gr) and there are significant differences in style, beyond the differential levels of wear. The top coin has sharper and narrower lettering compared to the second. There is size difference but it is minimal. Based on weight and production quality, I believe the top coin is from Charles the Bald and the lower coin is from Charles the Simple. This assumption is based on the belief that while there is significant inter-mint variation within reigns, same mint variation within reigns is more limited, and the differences in these coins pushes the limits of intra-mint variation.

Ruler     Type           Mint               Weight
CB        temple                             1.45
CB        Carlvs Rex     Orleans             1.69
CB        CR             Clermont            1.77
CB        CR             Palace              1.43
CB        CR             Toulouse            1.55
CB        GDR            Amiens              1.49
CB        GDR            Chartres            1.51
CB        GDR            Courcessin          1.58
CB        GDR            Laon                1.71
CB        GDR            Rouen               1.56
CB        GDR            St Denis            1.60
CB        GDR            Sens                1.63
CB        GDR            Tours               0.95   immobilized

CB/CF     CR             Bourges             1.50
CB/CF     CR             Nevers              1.63

CB/CS     GDR            Arras               1.63
CB/CS     GDR            Blois               1.54
CB/CS     GDR            LeMans              1.75    Charles the Bald
CB/CS     GDR            Melle               1.62
CB/CS     GDR            Orleans             1.70    Charles the Bald
CB/CS     GDR            Orleans             1.58    Charles the Simple
CB/CS     GDR            Paris               1.67
CB/CS     GDR            Paris               1.69
CB/CS     GDR            Quentovic           1.82    Charles the Bald
CB/CS     GDR            Reims               1.40
CB/CS     GDR            Rennes              1.23    Charles the Simple
CB/CS     GDR            Sens                1.63
CB/CS     GDR            Soissons            1.63
CB/CS     GDR            Troyes              1.59    Charles the Bald
CB/CS     GDR            Troyes              1.21    Charles the Simple

AR denier, 19mm, 1.59gr. Obv: +CRATIA D-REX, central monogram. Rev: +TRECAS CIVITAS, central cross.  R 1444; MG954 as CB; Dep 11:A1, 1084 (21 examples).

(for a larger version of this coin, click here)

AR denier, 19mm, 1.21gr. Obv: +CRATIA D-REX, central monogram. Rev: +TRECAS CIVITAS, central cross.  R 1444; MG954 as CB; Dep 11:A1, 1084 (21 examples). Based on weight, this is most likely a coin of CS.

Once again there are significant differences between these two coins from Troyes. The first weighs 1.59gr. v. 1.21 for the second. There are significant differences in production quality. The first has sharper lettering and a much more distinct KRLS monogram than the second. Based on these differences, I am reasonable confident the first is from Charles the Bald and the second is from Charles the Simple. By itself, the first would be harder to attribute based on weight along, but in comparison to the second, I think this is a reasonable assumption.