Complex sentence: The Peltasts themselves were armed lightly and used on forced marches by Philip V of Macedon in his campaigns, although they may have had a dual role, being mentioned in several battles they as forming part of the phalanx.
Split into simpler sentences: The Peltasts themselves were armed lightly and used on forced marches by Philp V of Macedon in his campaigns. Althoguh they may have had a duel role also as parts of the phalanx, as in several battles they are mentioned as being part of the phalanx.