As I mentioned last month, this month's coin is the extremely rare solidus of Valentinian III from Thessalonica which displays an obverse die link to the Valentinian III marriage (Valentinian III to Licinia Eudoxia) solidus - pictured below. It is well documented in historical references that after the wedding in Constantinople that the couple spent the Winter of 437/8 in Thessalonica on their honeymoon.

Notice that the two obverses are from the same die, but the upper coin has several indications of a later die state.  First, notice the die flow lines from the last 'N' in Valentinian (about 2 o'clock on the obverse).  They are much more pronounced on the Thessalonican piece than on the marriage solidus.  Next, notice the overall die wear that is displayed on the central devices, most noticeable on the helmet and drapery.  Since this piece is of full weight, 4.50g, the weakness in the obverse design has to be attributed to die wear as there was sufficient striking pressure as demonstrated by the indentation at the lower part of the bust which should have brought out the details of the die.  Therefore, it must be concluded that this coin was struck after the marriage solidus.

Now for the really interesting aspect of this coin.  The reverse of this coin demonstrates a previously unknown type and usage of dies.  If you look at the 'S' in the right field, you will notice that it has been recut over a 'V'.  Originally, this was a die that was for production in Ravenna.  Therefore, when Valentinian III went to Constantinople to get married it can be concluded that he brought with him a travel mint to supply the necessary coinage for his trip.  During the honeymoon it became necessary to strike additional coins (beyond what he brought with him and the marriage solidi that he had struck) and the die sinker took a Ravenna die and recut a 'T' and 'S' into the fields to represent that they were struck in Thessalonica.  Currently, this is the only know example and since it shares the same obverse die as the Valentinian III marriage solidi, the output must have been extremely limited.