Complex sentence: Dio implies that he did so out of cowardice, in order to avoid the imminent clash with the opposition, but it is more likely that he was pursuing an enemy cavalry force, which was possibly acting as a decoy.
Split into simpler sentences: Dio implies that he did so out of cowardice, in order to avoid the imminent clash with the opposition. But it is more likely that he was pursuing an enemy cavalry force, which was possibly acting as a decoy.