Complex sentence: It was probably in about 220 that local Persian governors (Ardashir I) started taking far and close lands; at the time, Artabanus did not pay much attention to his actions and decided to fight him when it had become too late.
Split into simpler sentences: It was probably in about 220 that local Persian governors (Ardashir I) started taking far and close lands. At the time, Artabanus did not pay much attention to his actions and decided to fight him when it had become too late.