Watch List notes:

The Eparch Collection of Roman, Byzantine and Islamic Weights
LATIN COIN WEIGHTS

Leo I, 457-474. Siliqua Weight (?) (Bronze, 12x12x2mm, 1.85 g 6), a square coin-weight on the reduced standard, Thessalonica. Diademed and draped imperial, beardless bust to right. Rev. Square monogram of LEONIS. A. Mazarakis, "A Byzantine check-weight of Leo I (457-474)" NomXhron 30, 2012, pp. 39-43 (this piece, illustrated on p. 39), Roma 10, 2015, 913 (same dies). A weight of great rarity and interest. Nicely patinated. Good very fine.

From the Eparch Collection, ex Helios 6, 9 March 2011, 1073.
This fascinating piece forms part of a very small series of weights known to have been produced in Thessalonica, albeit primarily for solidi (as Bendall 16 and Lanz, 159, 2014, 653 - 4.23 g). We can be sure that this weight and the two known solidus weights were struck at the same time because the monogram on their reverses was definitely cut by the same engraver. A further weight, ostensibly of this type but weighing 2.02 g (Helios 8, 2012, 546) and supposedly of billon (!) is so stylistically peculiar that one wonders what it is supposed to be! In any case, our piece here is one of the very rare weights that can be ascribed to a specific Roman or Byzantine emperor. Do note that two other examples of the present type have since appeared with Roma in London: 9, 2015, lot 866 (1.46 g) and the above mentioned piece from auction 10 (2.18 g). The weights of the two recent examples diverge so much from that of the present piece, which Mazarakis identified as a reduced siliqua weight, that it is possible that it might, after all, be a semissis weight!