Nummus - Diocletianus large head type, GENIO POPVLI ROMANI, Heraclea

The "large head" variety of Diocletian's nummus from Heraclea reflects an early phase of the Tetrarchic coinage reform launched in 294 AD, when the mint at Heraclea — only recently established as an imperial facility under the new four-emperor system — was still calibrating its dies to the revised weight standard. The oversized portrait bust is a diagnostic feature of this transitional moment, quickly abandoned as the mint normalized production.

Heraclea's early output under the reform is notably scarcer than that of longer-established mints at Trier or Lugdunum.