Complex sentence: The legion probably participated to the battle of Actium (31 BC), and later moved to Macedonia, where it stayed from 30 BC to AD 6, gaining its cognomen, then the legion moved to Oescus (Moesia).
Split into simpler sentences: The legion probably participated in the battle of Actium (31 BC). It later moved to Macedonia, where it stayed from 30 BC to AD 6, gaining its cognomen, before moving to Oescus (Moesia).