 Macrinus was at first occupied by the threat of the Parthians, with whom Rome had been at war since the reign of Caracalla.Macrinus settled a peace deal with the Parthians, after fighting an indecisive battle at Nisibis in 217.In return for peace, Macrinus was forced to pay a large indemnity to the Parthian ruler Artabanus V. Rome was at the time also under threat from Dacia and Armenia, so any deal with Parthia would likely have been beneficial to Rome.