Very fascinating! I love the bold countermark placement and the fact that it seems to read "PIES". Mmmmh, pies...
The mint workers were careful not to destroy the major devices on the obverse, normally placing the c/m either in front/behind the bust or in this case across the neck.
Wonderful OP @David Atherton , what great history and a great coin! LOL, @stevex6 had a BLOW-OUT of great Counter-marks! I only have one from the Roman period: Cilicia - Tarsos turret counterstamped Bow Pompei Pirates AE 19 164 BCE Tyche-Zeus seated Ex: the Eclectic @John Anthony ! And some INDIAN: India Mauryan or Sanga 3 India Mauryan or Sanga 3.4g Rect India Matsya AR Vimsatika 650-600 BC stamped bankers India Maurya ser VIB AR Karshapana punchmark 270-175 BC ASHOKA