It's a denarius of Septimius Severus, trophy with two captives type. The coin celebrates Severus' victories over Parthia, after which he assumed the title Parthicus Maximus, PART MAX on the reverse. PM TR P VIIII makes it RIC 176. A little rough, but a good and complete example of the type.
The reverse shows a military trophy( a hemet, spear, and uniform on a staff) and two parthians kneeling on either side of it crying.
thank you. RIC 185 Septimius Severus Denarius. 202 AD. SEVERVS PIVS AVG, laureate head right / PART MAX P M TR P X COS III P P, trophy of arms & armour with two Parthian captives seated either side at base. RSC 373.