I added this coin to my site: http://augustuscoins.com/index.html on this page: http://augustuscoins.com/Tetrarchy.html which emphasizes coins of the tetrarchal period and Constantinian coins. Maximian CONCORDIA MILITVM is very high grade. Look at the detail! XXI 21 mm. Officina EΔ for "5+4 = 9" because the usual letter for 9 is Θ (theta) which abbreviated "death" (thanatos) on legionary roles. Some emperors avoided the usual Greek 9 for the officina number for that reason. Not slabbed, but in (and photographed through) a hard plastic circular holder 36 mm in diameter. Holder provided at no additional cost . You will probably want to remove it. [$39 + $3 in the US, PayPal is fine] Really nice! Check out the site for more ancient coins and books about them for sale.
