Thanks to Dorothy King, I came across this solidus of Julian the Apostate at the 2011 April Heritage-Gemini Signature Ancient Coins Auction #3011. Lot 452 was a solidus from the mint in Constantinople. The reverse shows a soldier, helmeted and with flying cloak, advancing right, looking back, holding trophy over left shoulder and placing right hand on head of captive kneeling behind him with hands tied behind back. But the portrait is wonderful, the best I have seen on a coin. If only I had a spare USD16,100.

The other one I covet is this example from Julian's time as Caesar struck at the mint in Antioch. On the reverse Roma and Constantinopolis are enthroned facing each other, each holding a sceptre and supporting a shield inscribed with an eight-pointed star.