It has to be borne in mind that the shape of the incuse depressions on the reverse of coins is very constant. Thus on the Aeginetan coins we never find what is known as the mill-sail incuse which is the peculiar feature of the reverse of the early Boeotian coins, nor on the other hand do we even find the eight-fold incuse on the coins of Boeotia. Some influences must have determined the choice of form, such as I have just suggested in the case of Aegina. Did the first Boeotian Mintmaster shape his coins with the real buckler in his mind’s eye? On the reverse of these coins we find the incuse forming a rude X, which is bounded by a circle of dots, whilst in the centre of the incuse is the initial letter of the name of the issuing town, such as 𐌈 for Thebes, 𐌇 for Haliartus. Does the X-shaped incuse represent conventionally the cross-bars of the frame of the shield seen at the back, the circle dots indicating the outline? The letters on these coins are the earliest inscriptions on the coins of Greece Proper. We can easily see how they came to be placed on the coins, as soon as we remember that there was a Λ on the Lacedaemonian shields, a Σ on the Sicyonian, a Μ on the Messenian[410]. Why do not we find the initial in the coins placed on the front of the shield, where it must have stood on the real buckler? If as is held by the best authorities the coins of Boeotia formed a federal currency, we see a reason for the practice. As the silver shield replaced the real buckler, the old unit which had been universally employed through Boeotia, no town would have been permitted to put its initial on the shield engraved on the obverse. No doubt the old actual shield of currency was plain, and each purchaser painted the initial of his own country upon it. The Mintmasters accordingly of each town regarding the whole coin as a shield placed the letter of these several states on the reverse. Baumeister (_Denkmäler_, _s.v._ Wappen) gives pictures of the back of two shields. The frame of the shield consists of a circular rod, with two cross bars. The idea of making the incuse represent the other side of the object given in relief on the obverse seems to be just the stage between a complete representation of the object as in the tunny of Olbia, and that evinced by the early coins of Magna Graecia, on which the reverse gives in the incuse exactly the same form as that in relief on the obverse.